To be clear, Stripe is one of multiple payment processors OnlyFans uses. I don't know what the other ones are but they do have a processor that is more favorable for NSFW content, and all related payments go through that/those processors. Safer payments go through Stripe, at least last I checked.
Payment processors successfully got OnlyFans to ban sexually explicit content in 2021. The policy was just reversed before it ever went into effect - presumably the announcement generated some compelling data on how much less money everyone would make if the policy went through. (I don't know if this is also related to their transition away from Stripe for the NSFW-est content.)
