Beets is a decent and battle-tested solution. It has a Discogs plugin as well.

https://github.com/beetbox/beets

it takes a while to take a large library, but that's mostly because of intractable problems with ambiguity in metadata searching. I think it's about as fast as is reasonably possible.

My favorite thing about beets is that it doesn't stop processing when it needs user input. Meaning you can tell it to import a bunch of files, completely forget about it, and come back the next day and only give it input for the files that need it.

I wouldn't let an auto tagging solution anywhere near my collection - at some point it will get things wrong. However if you don't mind manually checking and editing tags I find Meta [1] to be an absolutely fantastic app.

Every new release that gets added to my collection will spend a few seconds in Meta so that I can check and edit the meta data and rename the files in a consistent way. Obviously you can also edit multiple releases at once.

I used quite a few tagging apps over the years, Meta is without a doubt the best of them.

[1] https://www.nightbirdsevolve.com/meta/