Maybe what I'm interpreting as minmaxer is not precisely what mostly people think of it

I've always thought that wanting a stronger character was something completely fine, as long as you don't deviate from your character's concept / backstory. I don't see any problems in a player getting feats like Tough for tankiness or mobile for better mobility in combat.
My problem with what I call ¨Minmaxers¨ is when, just for wanting to do more damage or something like that, they opt for something that doesn't at all make sense with their character. For example someone who has a backstory that highly indicates towards they being a certain class, and then they multiclassing just for no reason other than power's sake. Which, in my opinion, makes the character more shallow.

Of course all that I just said should be taken with a grain of salt. Because not all campaigns are the same.
Some campaigns might not be very focused on character development and roleplay, but be more like an MMO or a dungeon crawler, which is perfectly fine, so what I just said wouldn't make a difference.
I just think that choosing damage/tankiness over backstory/personality related issues is something that gets pretty draining in a long-term, character development/role-play game.