First, it was meant to be a joke.
Second, even if it was the case, I am nobody to judge. It's a legal professional activity, and adult performers, just like any other entertainment professionals, would be subject to visas as well in order to perform in the United States.
I happen to know adult performers and the adult entertainment industry, hence my quirky remark.
The way OP worded his/her question with the term "other social media collabs" is so vague that it can mean anything, from collaborations with U.S. brands on Instagram/TikTok etc..., but yes, also collaborations with other performers or U.S. studios on OnlyFans.