I can help you in extracting your business files to your new company file, @AllenE.
We can start by creating a copy of your existing company file. Then, condense the file to remove the transactions you want to exclude. This gives you a basic framework to use for your new company file. Here's how:
You should now have two separate company files: the original and the one you restored from a backup. You can now remove your current business file that you wanted to exclude in your 2019 and 2020 data. Here's how:
After you condensed your file, you can run a Transaction List by Date report to make sure the accounts you want to remove are gone.
If you need to know more about Condense Data utility and how it affects the size of your company file, you can check this article: Use the Condense Data utility.
Should you have any further questions or concerns about excluding your business files in QuickBooks, please let me know so I can provide you assistance.