Thanks for the feedback everyone!
The tables structure I provided earlier was a simplified version as I believed it will be sufficient, turned out I was wrong. Full table structure as below:
1) ann_events_Tech_Details
CREATE TABLE [dbo].[ann_events_Tech_Details](
[id] [bigint] IDENTITY(1,1) NOT NULL,
[events_id] [bigint] NOT NULL,
[ani] [nvarchar](20) NULL,
[dnis] [nvarchar](20) NULL,
[lang] [nvarchar](5) NULL,
[source] [nvarchar](50) NULL,
[call_flow_name] [nvarchar](50) NULL,
[start_time] [datetime] NULL,
[end_time] [datetime] NULL,
[tech_max_sn] [bit] NULL,
[tech_max_sm] [bit] NULL,
[tech_max_mobile] [bit] NULL,
[tech_hangup] [bit] NULL,
[tf_tech_home] [bit] NULL,
[tf_tech_reconnect] [bit] NULL,
[tf_tech_critical] [bit] NULL,
[tf_tech_del] [bit] NULL,
[tf_tech_business] [bit] NULL,
[tf_drop_tech_home] [bit] NULL,
[tf_drop_tech_reconnect] [bit] NULL,
[tf_drop_tech_critical] [bit] NULL,
[tf_drop_tech_del] [bit] NULL,
[tf_drop_tech_business] [bit] NULL,
[sel_tech_dialup] [bit] NULL,
[sel_tel_nodialtone] [bit] NULL,
[sel_tel_noisy] [bit] NULL,
[sel_tech_internet] [bit] NULL,
[sel_tel_csr] [bit] NULL,
[sel_tech_ckc_disconnect] [bit] NULL,
[sel_tech_ckc_transfer] [bit] NULL,
[sel_tech_tel] [bit] NULL,
[sel_tech_other] [bit] NULL,
[tech_sni_success] [bit] NULL,
[tech_sni_failure] [bit] NULL,
[tech_tos] [bit] NULL,
[tech_tt] [bit] NULL,
[tech_ckc] [bit] NULL,
[tech_tt_creation_success] [bit] NULL,
[tech_tt_creation_failure] [bit] NULL,
[tech_consumer] [bit] NULL,
[tech_business] [bit] NULL,
[tech_time_warranty] [bit] NULL,
[tech_dat] [bit] NULL,
[last_menu_selection] [nvarchar](200) NULL,
[service_number] [nvarchar](20) NULL,
[sn_invalid_count] [int] NULL,
[sn_success_count] [int] NULL,
[sn_timeout_count] [int] NULL,
[sn_error_count] [int] NULL,
[mobile_num] [nvarchar](20) NULL,
[tt_number] [nvarchar](20) NULL,
[tt_invalid_count] [int] NULL,
[tt_success_count] [int] NULL,
[tt_timeout_count] [int] NULL,
[tt_error_count] [int] NULL,
[ckc_invalid_count] [int] NULL,
[ckc_success_count] [int] NULL,
[ckc_timeout_count] [int] NULL,
[ckc_error_count] [int] NULL,
[sel_bill_statement] [bit] NULL,
[sel_bill_payment] [bit] NULL,
[sel_bill_transfer] [bit] NULL,
[sel_bill_paybill] [bit] NULL,
[tf_bill] [bit] NULL,
[tf_drop_bill] [bit] NULL,
[pbstat_invalid_count] [int] NULL,
[pbstat_success_count] [int] NULL,
[pbstat_timeout_count] [int] NULL,
[pbstat_error_count] [int] NULL,
[ciw] [bit] NULL,
[tf_pulse] [bit] NULL,
[tf_drop_pulse] [bit] NULL,
[tech_max_ss] [bit] NULL,
[ss_timeout] [bit] NULL,
[ss_icp] [bit] NULL,
[ss_nova] [bit] NULL,
[ss_tmgo] [bit] NULL,
[ss_wifi] [bit] NULL,
[ss_invalid] [bit] NULL,
[sel_inv_del] [bit] NULL,
[sel_inv_unifi] [bit] NULL,
[tf_wifi] [bit] NULL,
[tf_drop_wifi] [bit] NULL,
CONSTRAINT [PK_ann_events_Tech_Details] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_max_sn] DEFAULT ((0)) FOR [tech_max_sn]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_max_sm] DEFAULT ((0)) FOR [tech_max_sm]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF__ann_event__tech___18D6A699] DEFAULT ((0)) FOR [tech_max_mobile]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_hangup] DEFAULT ((0)) FOR [tech_hangup]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_tech_home] DEFAULT ((0)) FOR [tf_tech_home]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_tech_reconnect] DEFAULT ((0)) FOR [tf_tech_reconnect]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_tech_critical] DEFAULT ((0)) FOR [tf_tech_critical]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_tech_del] DEFAULT ((0)) FOR [tf_tech_del]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_tech_business] DEFAULT ((0)) FOR [tf_tech_business]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_tech_home] DEFAULT ((0)) FOR [tf_drop_tech_home]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_tech_reconnect] DEFAULT ((0)) FOR [tf_drop_tech_reconnect]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_tech_critical] DEFAULT ((0)) FOR [tf_drop_tech_critical]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_tech_del] DEFAULT ((0)) FOR [tf_drop_tech_del]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_tech_business] DEFAULT ((0)) FOR [tf_drop_tech_business]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_tech_dialup] DEFAULT ((0)) FOR [sel_tech_dialup]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_tech_nodialtone] DEFAULT ((0)) FOR [sel_tel_nodialtone]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_tech_noisy] DEFAULT ((0)) FOR [sel_tel_noisy]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_tech_internet] DEFAULT ((0)) FOR [sel_tech_internet]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_tech_other] DEFAULT ((0)) FOR [sel_tel_csr]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF__ann_event__sel_t__15FA39EE] DEFAULT ((0)) FOR [sel_tech_tel]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF__ann_event__sel_t__16EE5E27] DEFAULT ((0)) FOR [sel_tech_other]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_sni_success] DEFAULT ((0)) FOR [tech_sni_success]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_sni_failure] DEFAULT ((0)) FOR [tech_sni_failure]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_tos] DEFAULT ((0)) FOR [tech_tos]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_tt] DEFAULT ((0)) FOR [tech_tt]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_ckc] DEFAULT ((0)) FOR [tech_ckc]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_tt_creation_success] DEFAULT ((0)) FOR [tech_tt_creation_success]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_tt_creation_failure] DEFAULT ((0)) FOR [tech_tt_creation_failure]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_consumer] DEFAULT ((0)) FOR [tech_consumer]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_business] DEFAULT ((0)) FOR [tech_business]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tech_time_warranty] DEFAULT ((0)) FOR [tech_time_warranty]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF__ann_event__tech___17E28260] DEFAULT ((0)) FOR [tech_dat]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sn_invalid_count] DEFAULT ((0)) FOR [sn_invalid_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sn_success_count] DEFAULT ((0)) FOR [sn_success_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sn_timeout_count] DEFAULT ((0)) FOR [sn_timeout_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sn_error_count] DEFAULT ((0)) FOR [sn_error_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tt_invalid_count] DEFAULT ((0)) FOR [tt_invalid_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tt_success_count] DEFAULT ((0)) FOR [tt_success_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tt_timeout_count] DEFAULT ((0)) FOR [tt_timeout_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tt_error_count] DEFAULT ((0)) FOR [tt_error_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_ckc_invalid_count] DEFAULT ((0)) FOR [ckc_invalid_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_ckc_success_count] DEFAULT ((0)) FOR [ckc_success_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_ckc_timeout_count] DEFAULT ((0)) FOR [ckc_timeout_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_ckc_error_count] DEFAULT ((0)) FOR [ckc_error_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_bill_statement] DEFAULT ((0)) FOR [sel_bill_statement]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_bill_payment] DEFAULT ((0)) FOR [sel_bill_payment]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_bill_transfer] DEFAULT ((0)) FOR [sel_bill_transfer]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_sel_bill_paybill] DEFAULT ((0)) FOR [sel_bill_paybill]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_bill] DEFAULT ((0)) FOR [tf_bill]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_bill] DEFAULT ((0)) FOR [tf_drop_bill]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_pbstat_invalid_count] DEFAULT ((0)) FOR [pbstat_invalid_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_pbstat_success_count] DEFAULT ((0)) FOR [pbstat_success_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_pbstat_timeout_count] DEFAULT ((0)) FOR [pbstat_timeout_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_pbstat_error_count] DEFAULT ((0)) FOR [pbstat_error_count]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_ciw] DEFAULT ((0)) FOR [ciw]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_pulse] DEFAULT ((0)) FOR [tf_pulse]
GO
ALTER TABLE [dbo].[ann_events_Tech_Details] ADD CONSTRAINT [DF_ann_events_Tech_Details_tf_drop_pulse] DEFAULT ((0)) FOR [tf_drop_pulse]
GO
2) ann_ReportItem
CREATE TABLE [dbo].[ann_ReportItem](
[id] [int] IDENTITY(1,1) NOT NULL,
[report_id] [int] NULL,
[report_item] [nvarchar](100) NULL,
[report_item_id] [int] NULL,
[call_flow_name] [nvarchar](50) NULL,
[source] [nvarchar](50) NULL,
[remark] [nvarchar](500) NULL,
CONSTRAINT [PK_ann_ReportItem] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[ann_ReportItem] WITH CHECK ADD CONSTRAINT [FK_ann_ReportItem_ann_Reports] FOREIGN KEY([report_id])
REFERENCES [dbo].[ann_Reports] ([id])
GO
ALTER TABLE [dbo].[ann_ReportItem] CHECK CONSTRAINT [FK_ann_ReportItem_ann_Reports]
GO
SQL Execution Plan is attached as well.