Ryan Haywood from Rooster Teeth was fired after a number of allegations that he was cheating on his wife with fans. These allegations also included statutory rape and sexual assault. Some evidence was provided to corroborate the allegations. Rooster Teeth removed some videos involving him and publicly distanced themselves from him. He tried to make a comeback on Twitch and got a ton of pushback from it. I believe he ended up getting banned shortly after.

I would say Internet Historian, after his plagiarism debacle.

JonTron got too big for his britches, fucked off of GameGrumps and then on a podcast popped off the “50% of crimes are committed by 13% of the population” horseshit and then kept doubling down on it, now he makes just garbage tier reaction videos like once every 6 months

Similarly RubberRoss’ cosplayer wife cheated on him with ProJared in what may have been the most pathetic public cuckoldry since Hogan famously belched “I can’t fuck brother! I ate too much sushi” so Holly and Jared both fell apart after that

I don’t know if he counts as a YouTuber because he got canceled on twitch and moved to YouTube but Dr Disrespect live streamed himself at TwitchCon including going into the public restroom where there were minors present. Which is a bad look but could maybe be seen as an accident if it didn’t also come out that he was actively cheating on his wife, whom he had a child with, with women he was meeting with from Twitch. It was all a bit too much and his platform collapsed while he also started firing off lawsuits in multiple directions