The OnlyFans promoters are there, they just do a better job at hiding in plain sight. Usually when you see an "F4M" post where the woman talks about how thirsty she is, all you need to do is click her profile and check on some other posts/comments.

Smart OnlyFans promoters don't advertise directly on the profile if their goal is to use R4R subs to advertise their product. Chances are that you'll see a comment in an OF sub though that belongs to the profile in question, linking back to their page.

Or the promoter is waiting till you DM them to share that link. Either way, they still present themselves as regular people until you get a little closer. All in all, they just waste your time.