What's interesting about Nick's theology is that there is no church with a doctrine encompassing all his beliefs, so he must (at least in part) see himself as the arbiter of truth.
Yes. Many people do this to some extent as they agree, disagree, or agree to disagree on certain points with their church. This is usually where discernment becomes important in identifying false prophets, teachings, and anything that would lead one astray. Sometimes it leads someone from one church to another, ideally in the pursuit of truth. Nick can decide what he believes, but he is far from the arbiter of truth.
Nick is obviously bothered by his predicament though, even if it just comes down to social pressure, and he is unequipped to handle situation if all he brings to the table are questions, his own passions, and an indignant posture. Every time Nick complains about the prudes in his community online he makes it more difficult to face them.
Overall, it reminds me of Nick's Locals when they first realized that
@Yandex Captcha Solver and others were reposting their lewds here for us to laugh at. They went from "not caring" to coping to self-conscious over time as they slowly realized what posting in a public chat meant. Similarly, Nick seems to be realizing that making degen content and telling people to "fuck off" on the Internet hits different IRL, especially when his family shares the same space as them. For of Nick saying that he "can't control what people say about him", not openly posting dumb perverted crap about oneself certainly helps.
Nick needs other people more than he cares to admit. His desire for exhibitionism has shown that, and it's getting to the point where he can't even achieve ball-gasm with his wife unless other people at the resort are watching.