New to BMW, what series models/years to consider and avoid?

Hey gents! I have a 30minute commute one way, and wanting to get out of my truck for something smaller. I also want a fun/sporty daily commute as a replacement. I've been looking at the Detroit 3, and I am now looking at BMW and Mercedes.

I can afford a 2015-2020, 4-6 series coupe without breaking the bank (from what I've researched. Something like a 440, 550, etc., or even a 4 door 3 series of same caliber.

This would be both my first luxury and power/sporty vehicle. I always hear bad things about Bimmers, but people always buy them, and I'm always intrigued.

With that, IDK anything really about BMWs, and want to know what models and years I should outright avoid, and what to consider within the range. I'll appreciate the advice from this community!

Quick Edit: I did try to do a search in the community first and didn't really see anything, so if you guys have a link to a post on the topic, that'll be dope as well.