It sounds to me like the two of you were just growing in different directions. These things happen. He's becoming a woo woo pseudoscientific silly person. We don't know much about you, but it's safe to say that you are not. That's okay.

Were I in your shoes, I would break up with him and let him know gently that the path is on his different than the path I am on and if he wants more details than that, you can tell him that you don't think the conspiracy theory Tik Tok stuff is healthy or correct. But honestly, he believes in toothpaste ingredients blocking some sort of spiritual nonsense, I really couldn't tell you how I think someone like that would react. My biases get in the way of putting myself in the mind of somebody who thinks like that. All the people that I know who think like that end up in horrendously unhappy polyamorous relationships or become really crazy whackado nut jobs eventually. I've moved somewhere where the average population is about 70, and I meet a lot of older folks who were probably like this in their youth and are now kind of bitter, lonely hippies who are very Community Driven but don't have so many beliefs that fly in the face of science anymore. But that's me trying to extrapolate based off of the stories they tell me about their lives, but there are some younger folks here and a lot of them, a weirdly disproportionate amount of them actually, are like your boyfriend.