It thankfully seems to have been fixed thanks to @graycube@lemmy.world. Running analyze verbose;
in postgres.
The pgautoupgrade was added for the new version because this deployment is an all-in-one solution for running lemmy. And upgrading the databases turned out to be quite the effort until some user pointed the maintainer towards pgautoupgrade here.
I tried running lemmy before I found out about this, but this just makes it so much more convenient to run.
Well that would do it. Thanks for pointing out!