Ive also got this problem, but to be honest, I think iTunes has been a mess for a while. For me, it was at its best circa 2010, when you could still open playlists in separate windows. Which if you're a serious music collector like myself, was very handy when cataloging my tunes!
Ive got a massive music collection, all physical discs imported to iTunes (almost half a years worth of solid listening!) and Ive spent years organising it all into playlists that make sense to me (kind of like back in the 90s when it was only 'you' in control of how your music was set out), so it really burns my arse when Apple come along with changes they deem worthy for the masses that grate with my organisation.
I'll take the old iTunes over this overly glossed rubbish, built for people who just plonk music in without thought (and there's nothing wrong with that, but it doesn't work for me!). To be fair, it pretty much lets me do that now still, it's just a lot slower than it was, I just want the 'open playlist in a separate window' feature to return and a promise that my 10 years of cataloging isnt going to get screwed up by an update!
But yeah, back to the topic, version 12.2 is incredibly slow!