I used to watch him years ago. He has a very young and impressionable audience which he constantly feeds memes with right-wing rethoric.

To list a few of the stuff I remember:

• He said the N word hard R;
• He paid people on Fiverr to show a sign saying "Death to all Jews" or something like that, where he laughed at the reveal. He said it was to prove a point that you could do harmful shit with that type of online service, but all it ended up doing was getting the guys banned from the platform and served to signal to Nazis that he would host such content;
• He allowed right-wingers to fester in his community, 4chan specially really liked the guy;
• He hosted both Ben Shapiro and Elon Musk in his channel for a "meme review";
• He has stated multiple times that his favorite author is Mishima, a Japanese fascist, not only in the past, but also in the last year at least;
• He used to stream on some crypto bullshit site, which I don't remember the name;
• His whole campaign against the Indian conglomerate T-Series lead not only to racist comments but also to a very racist music video he did;
• The Christchurch shooter mentioned him in a video. And while being mentioned by a shooter doesn't necessarily mean he's an issue, in this case it's extremely relevant since it's pretty clear that is a byproduct of his politics and the community he has.

There's probably much more that I either don't remember or don't know about, but this is more than enough to understand where he stands politically and the harm he causes.

I also recommend the video: The PewDiePipeline.