I think what happened was:
He was obsessed with making it as a successful YouTuber to the point where it started to become a genuine threat to his mental health and wellbeing.
It certainly was affecting his real life relationships.
Being that his biggest success was appearing with Chris, his audience was largely gay men, and he didn't really want to cater to that audience.
I think probably the level of queer attention, versus the lack of any real success probably made him realise that he'd gone down a rabbit hole that he needed to get out of.
Especially after attending gay events with Chris and getting alot of that gay attention in person.
Chris will just attach himself to whatever is popular and act up his gayness or sluttiness or innocence depending on what he's doing, he's not renowned for being that genuine.
But I think Calvin was a genuine, innocent guy that kind of got caught up in something and had to cut it all off to start over.
I hope he stays off socials and just gets a job, an apartment, meets a girl, and has a normal life.