I went ahead and used the Migration Tool.  Looks like it worked.

BACKUP:

In ProSeries 2021 (old computer):

1. Select Migration Tool.

2. It will ask if you want to continue and it will close Pro Series 2021.

3.  The Migration Tool will open up and you can select which years you want to back-up (on left side) or restore (right side).

4.  As you select the years it will list what you want to back-up or restore.

5.  Once confirmed it will write a back-up to your Desktop and open a link there.

RESTORE:

In new computer:

1.  Make sure you have loaded the Tax Years that you want to migrate.  It let me do 2019, 2020 and 2021.  2018 is Windows 7 only and at this time I am not going to mess around for Windows 7 compatability mode and will keep the software on my old computer.

2.  Open Migration Tool.

3.  It will ask where is the back-up so point to the file on the flash drive etc.

4.  It will list what software is there.  Select what you want to restore.  Click through.

5.  It should be relatively fast on our newer machines.

6.  Once finished, go into the respective years Pro Series and click through and it should have populated all your company information and then once done you will see all your clients.

Nice work, Intuit.

Update:  ProPDF files did not look to be part of the migration but those are easy to copy in bulk from the old computer to the new one.