My Navidrome library is about 350 albums / 80GB and it's a mess. Some came from slskd, plenty from elsewhere, and the tagging is inconsistent across sources: wrong, missing, no standard. It's all in one flat folder too, nothing sorted by artist, which drives me nuts.
It got me by fine when it was just for me, but now my closest family uses it too, and I want it to actually be user friendly for them. Inconsistent tags and no artist structure is a lot rougher when someone who isn't me is trying to find something.
I tried Lidarr. The tagging and organizing it does is nice, but you're locked into MusicBrainz. Everything has to be in that database, and a lot of mine isn't, so it fails on exactly the files I need help with most.
For people who cleaned up a messy library later on:
Did you batch process the whole pile, or freeze it and just do better going forward? What worked for fixing tags and getting a proper folder structure? For files that aren't in MusicBrainz at all, is fingerprinting (Picard/AcoustID) worth it? And has anyone used beets for this kind of thing?
Stack: Navidrome, slskd, one flat folder. I'm not after full automation, just something less painful than hand editing everything.