@kara_dreamer They offer a variety of play modes:
Training - just you and some bots
VS AI - team of players vs team of AI
Quick Play - players vs players, outcome does not affect your "competitive rating"
Competitive - players vs players, outcome affects competitive rating (people can get really salty in here)
Arcade - fun stuff

Every now and then they'll also have story-driven PVE scenarios that are players vs AI.

Lots of options to play without running into toxic types