So I finally tried a file copy using Copy or Backup File for my 600MB file with transactions dating back to early 2000's.
Under Advanced Options I chose: Create a copy or template
On the Copy or Template screen
Include transactions from: 1/1/2019-2/7/2027.
Include: Uncleared transactions, Investment Transactions (Do not include attachments)
After saving the copy the file size of the copy was quite smaller (250MB down from 600MB). However when I opened the copy and checked the history of various accounts including checking/savings etc., transactions that pre-date 1/1/2019 are present in the copy. Old accounts that were closed way before cutoff are still there. This is not how I expected this operation to work. In fact, other than the smaller file size, the content of this file is indistinguishable from the original file. Is this how copy with date range is supposed to work?