Wasn't there a straight Thai couple that got arrested a few months ago for publishing videos their sex videos?
So yeah, producing and distributing pornography is technically illegal in Thailand and I think onlyfans didn't process payments in Thailand for a while.
That said, i know a few people doing onlyfans in Thailand, albeit they don't make videos that often.
I think there are even more profiles if you are looking for just thai-on-thai action.
I was talking more about professional or semi-professional porn (you have at least one camera operator filming it).
It's not like there hasn't been any cause as I said there has been: crazymonkey, badmanrobin, pablo_bravo, privateboymovie, laughingasians (I think he is based in the Philippines), etc but way less compared to straight porn being filmed in SE Asia and most of them are actually from quite a few years ago.