Honestly, by online gaming standards, I’ve found Dota pretty tame. Prehaps its just because I stick to more casual modes and have a high behaviour score, but I rarely see much more than a “GGEZ” at the end of a game, or players tipping mistakes. I think its been at least a month since the last time I saw someone hack, intentionally teamkill, or throw. Obviously, its still a competitve online game (toxicity isn’t rare), but the only other online game I can think of where I experienced less toxicity was Deep Rock Galactic.
Its possible I’ve just been lucky enough to avoid that part of the playerbase. Then again, my perception my also be skewed from spending so much time in Dead By Daylight, War Thunder, Minecraft and Counter Strike. At least in Dota, it takes some effort to kill more than a couple teammates.