Hello,

This is more a question then a bug report, because I don't think it actually is a LP issue but I can't figure out what it is.

So basically I set a prefix to a group but /lp group [grp] info shows no prefix, and it also doesnt show up in the user info. I looked with verbose but I don't see what the issue is, I think something might overwrite the LuckPerms prefix provider.

Here is the verbose session:
https://luckperms.net/verbose/#WUyv46pC7b

and here a editor session to see that I should have a prefix:
User: https://editor.luckperms.net/jPXCwQBF0M
Primary Group: https://editor.luckperms.net/BXaMIQ6epg

Prefixes are stored in the group's meta. Check /lp <group> meta info

Huh, well there the prefixes show up, but the verbose log still shows them as nil, as well as in the user info ( which should show the users Prefixes ), so this still doesnt explain why they don't show up

Try deleting the group and creating the prefix again with this command
/lp <group> meta setprefix 0 <prefix>

Already tried that, and also tried setting a prefix to the user directly. I am 100% convinced that one of the addons causes that, LuckPerms is fine and doing what it should do, but one of the plugins tries to overwrite the Prefix Provider

Most likely.

Try resetting your LP config file, sounds like you've tweaked a setting there which is causing it to return nil.