Understandable, I will say you definitely chose to dive straight into the deep end choosing Lemmy 🤣 I think most people cut their teeth using docker on stuff like Plex and the related *arrs, then jump to the more complex stuff.
But, it’s also the best way to learn so enjoy it :) stuff like this will become trivial eventually
This is the solution to your problem
Change your config to mount the data directory to /var/lib/postgresql instead of /var/lib/postgresql/data
My advice though, if your debugging skills are primarily comprised of asking AI for help, you’re in for a bit of a learning curve. The software is absolutely amazing (I’ve been running an instance since 2023), but weird things pop up and because this is so niche quick google searches are very limited and you gotta be willing to dive into github issues (this for example, I’ve also had to do it for pictrs to debug something a while ago).
Don’t feel discouraged though, this is probably the most rewarding thing I host (more than plex, immich, or any of the other “mainstream” things people talk about)
Editing to add, i know this is the fix because I had to reinstall lemmy from the ground up (long story) a few weeks ago and had the same issue :)
try this
But, make a backup of your db beforehand. I don’t know how it would work when upgrading an existing database