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.
What limitation did you encounter?
As you mention, 20220803.1 does appear to run significantly slower for us than even 2.0.2, on every page.
Wow, slower than 2.0.2. That's disappointing.
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.
Maybe it's a good idea to stay with version 2.4.24 for the production/real system.
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.
Thank you for your effort. I hope, that, looking from different perspectives onto the issue, more eyes see more.
I have tried running the site on PhP 7.4, 8.0, and 8.1, and haven't noticed much if any difference either.
Regarding to the database connection performance issue I wouldn't expect the PHP version to have a great influence.
Trenne niemals Müll, denn er hat nur eine Silbe!