SELECT in the CROSS APPLY is more flexible, in that it makes it easier to assign multiple alias names and allows for table access to be part of assigning an...

Somewhat confusing, but I think this may return the rows you want:

SELECT T.*, Z.*
FROM
#TEMP1 T
INNER JOIN
[TSI].[ZATS_BROKER_FEED] Z
ON T.Part_Num...

Non-clustered index(es) are almost always a waste of resources on a staging table.  

A clustered index is much more likely to be useful, although it's obviously not guaranteed to...

You don't really need a cursor for what you're described.

DECLARE @job_name_pattern nvarchar(128)
DECLARE @sql nvarchar(max)

SET @job_name_pattern = 'MyJobEvery%'

SELECT @sql = CAST((

set statistics io,time off

DROP TABLE latestrecords ;
GO
CREATE TABLE latestrecords
(
Id int,
Email varchar(200),
Customer_FirstName varchar(200),
Status varchar(200),
RecordTimestamp DATETIME
)
GO

The imperfect index definition is a drag on the first query, requiring a sort of all rows.  Correcting the index definition:

DROP INDEX IX_latestrecords_1 ON latestrecords;
CREATE UNIQUE INDEX...

Not enough details to get specific, but in very general terms, I would likely go with a new option.

Keep the existing tables to do the current logging, but...