I've now completed a test upgrade to 20220803.1. The upgrade went fairly smoothly once I got a hang of the process and some cPanel File Manager limitations.

As you mention, 20220803.1 does appear to run significantly slower for us than even 2.0.2, on every page. Based on yours and Daniel's comments, I understand the DB changes from MyISAM to InnoDB, and the additional spam features added seem to be the primary culprits. Note that 2.4.24 provided the (significantly) best performance for us across all upgrade steps.

I'm going to take a look at the current DB structure a little more and see if anything stands out from a SQL performance perspective. The fact that performance is slow on every page, including Users / Admin / Forum Settings, etc, is a bit surprising here. I have tried running the site on PhP 7.4, 8.0, and 8.1, and haven't noticed much if any difference either.