declare @Seconds int = 31578
select @Seconds [@Seconds],
       t.Hours, 
       u.Minutes, 
    ...

If you don't already have similar indexes try these two indexes and see if there is an improvement:

create index IX_Cuentas_1 on dbo.Cuentas(idCuenta) INCLUDE (idjerarquia,Cuenta)
create index IX_Cuentas_2 on...

--DECLARE @CurrentDate as date='2020-11-25'
DECLARE @CurrentDate as date='2020-12-10'

;WITH Data (Id, WeekName, WeekDate) AS (
    SELECT 5, 'Gameweek 1', CONVERT(date,'2020-12-01')
    UNION
...

--DECLARE @CurrentDate as date='2020-11-25'
DECLARE @CurrentDate as date='2020-12-10'

;WITH Data (Id, WeekName, WeekDate) AS (
    SELECT 5, 'Gameweek 1', CONVERT(date,'2020-12-01')
    UNION
  ...

DECLARE @Data TABLE (Name nvarchar(100));
INSERT INTO @Data(Name)
VALUES 
('Microsoft Windows NT Workstation 10.0'),
('Microsoft Windows NT Workstation 10.0'),
('Microsoft Windows NT Workstation 10.0'),
('Microsoft Windows NT Server 10.0'),
('Microsoft Windows NT Workstation...

Why have you got DISTINCT in the select from the table variable, can't you make a table variable with distinct values already in it?

Create a primary key or an index...

How do you know when the job last ran?

You might not need a variable and just use a subquery to get it.

Where...

WHERE (Insert_date > @LastJobRun OR Last_Updated > @LastJobRun)

That's very odd code. It looks like whoever wrote it didn't know you...

https://support.microsoft.com/en-us/help/3177312/kb3177312-sql-server-2016-build-versions

SQL Server 2016 Service Pack 1 (SP1) Cumulative Update (CU) Builds

SP1  13.0.4001.0 KB3182545   November 16, 2016

Do you have any indexes on the table you are inserting into?

If there are and it's loading into an empty table then it would be faster to disable all indexes...

If possible I always revert to standard UPDATE and INSERT instead of using a MERGE, this will give better performance. This is also the recommendation from Microsoft: "Performance Tip: The...

I was thinking more about this - realized we can do this:

SELECT weekend_day_count=y/7-x/7+(y+1)/7-(x-1)/7
   FROM (VALUES(DATEDIFF(DAY,-53690,'1899-01-01') + 1,DATEDIFF(DAY,-53690,'1900-01-14') + 1))x(x,y)

We can specify the anchor date...

How is a  DiagnosisCode flagged as special in dim_OHADiagnosis?

How is a row in  dim_Mapping identified as a Cancer Site diagnosis?

Which columns are used to join the tables together?