I took a nap so left it alone for a while, bumped remote_post_retention_days down to 28 (not that it matters here, I had meant to do that anyway), restarted pleroma, then ./bin/pleroma_ctl database vacuum analyze and rebooted when done. So far, memory is still higher than I remember it being in the past, which you’ve already explained, but swap is lower, and things that weren’t loading are loading fine, and I haven’t seen any more gateway timeout errors.
If I get issues again, could it be helpful to purge old remote content and do a vacuum full? Is it a good idea to do that periodically anyway? And should I stop my pleroma service while doing so or just expect it may cause a few hours downtime?
Appreciate your help and anyone reading this who might be inspired to chime in! Best