Below is a re-coded version of the stored proc.  It does the UPDATE of IsUsed inline, to reduce (eliminate?) chances of two near-same-time execs of it getting the same NextID...

1) How is clustered?  By ( Col, Col1) or something else?

2) How is normally searched?  By ( Col, Col1 ) or by something else?

3)...

INSERT INTO dbo.exportLogTable
SELECT
  ...list_of_all_columns_in_table...
FROM (
  SELECT *, ROW_NUMBER() OVER(PARTITION BY tableID ORDER BY tableID) AS row_num
  FROM dbo.exportLogTable2
) AS elt2

Not a good idea.  A direct SELECT ... INTO new_table can cause system table locking and can cause concurrence issues.  You should...

To the OP:
I still wish you'd run the script I posted earlier and post the results (on Page 4; can't get the link to it to copy correctly right...

You want five separate stored procs regardless.  Then, if you want only to have to call 1 main proc from the report/SSRS/whatever, create a parent/"driver" proc that executes those 5...

For [AMT].[ItemVersions] :
If [Description] and [PropertyBag] are (1) used more than rarely *and* (2) are used in at least 1 time-critical task *and* (3) for a majority of rows,...

Definitely need index overhauls.  [And wow do you all love guids!]  Would you mind running the script below and posting the results?  I always prefer to tune including actual SQL...

With the size of modern drives, and the number of files on each drive, I don't know that you truly get a stationary head sitting there waiting for the next...