Some maps and games are more likely to flame than others.
My advice - stay clear of setons and dual gap, people get very angry over small things and/or not playing the way they expect.
3v3 matchmaker is usually fairly chill (but there are exceptions), partly because there's less of a pre-set meta
Astro craters maps used to be relatively chill as well but it's been a few years since I've played them
there are occasionally team games vs AI which are fairly rare to have flaming
inevitably you'll come across some people who are toxic, but it's definitely a relatively small minority of games I play (I usually play 3v3 TMM). There's also 1v1 where it's less likely since there's no teammate to complain about how you play.
