there may be a lot more to it.

first how are you extracting from DB2
- Direct connection from SSIS (OLEDB or similar)
  -- in this case...

as a alternative method 

constraints
- PERIODYTD date is always greater or equal to PERIOD
- difference between the 2 dates is less or equal 3647 -- just shy of 10...

assuming there are no code changes between the 2 procs it is possible someone set option XACT_ABORT globally on the old server.

dbcc useroptions -- if output shows xact_abort...

seems to be true - https://docs.microsoft.com/en-us/sql/integration-services/install-windows/upgrade-integration-services?view=sql-server-2017

And its not like you were migrating from 2008 R2 - that one didn't had either as a feature except as a legacy...

Do have a look at this thread - https://www.sqlservercentral.com/Forums/1974006/convert-date-to-numeric#bm1974016 - and setup some test cases to see if your data suffers the issue mentioned on it around how Excel deals...

Running a job like that isn't really an overkill - on our main prod servers we have jobs running every 10 seconds. Very fast jobs though.

For data transfer...

compress definitely works a lot better for particular data - As an example one of my tables (700Million rows, 900GB + on standard format and page compression), when I compress...

and what is the sql you tried so far?

All functions you mention from excel can accurately be done in SQL with a possible exception of yearfrac - as...

well. the first link shown on google search has one that does give you the backup times - no duration as that is not available on msdb.
For duration you...

have you even bothered googling for the answer?

https://www.google.ie/search?q=sql+server+restore+history+mssqltips

Both BIDS/SSDT and the gui are 32 bit - server is running 64 bit so this is most likely the issue
install the 64 bit version of that component -...