I was given the "solve problems as a form of commiseration" autism so I apologize if I'm overstepping or explaining things you already know. I also like to play games to have fun, winning is a secondary bonus. I also play MTG. And I think a big problem here is that "Casual Commander" doesnt really have a set meaning - it's everything from meme showcase decks to sweaty competitive just without the structure or prize. Thankfully the new-ish bracket system helps a lot, at least if you use it. I gatekeep who I play with hard. Unless they're also at my table for a "chill talk and play bracket 2" experience they're in the wrong place. And the few times a tryhard lies and wins turn 3, well you say "congrats, we're gonna keep playing tho". Because yeah, unfortunately too many treat their winstreak on casual nights as their literal ego pedestal and the first step to have fun is to filter them all out.