You are getting lots of advice to dump him right away which i can see with lots of red flags here. The constant J Peterson and misogyn are both large red flags that needs to be addressed. Presumably you live together since you talk about shared finances. If you went on one date with this guy I would say run but since you have been together for longer you might want to stay a little longer. This depends on if this behavior seems out of character for him based on your history together.
I would suggest you talk with him about you concerns about quitting his job maybe with a couples therapist. He seems like he is miserable and doing anything to change that up but quitting a job to do streaming full time is not a great idea. Talk about how you want to find something that brings him joy in his career and will support him as he finds a realistic way to do so. This may be keeping his current job while start streaming on the regular or find a new job or new hobby / side hustle.
I do think he might need therapy to talk about these feelings with someone else. The Manosphere attracts unhappy men with no / little support. He might need more from a therapist ( maybe a male one) to talk this through. These seem like signs of a desperate for a change man.
Its never to early to read The Hobbit to get someone a lifelong addiction to the LoTR. I was trying for in-utero but my wife was not interested.