Yes. Does Instagram ban direct links to onlyfans? Because based on the logic presented here of a solicitation accusation, it should be. But obviously I agree with Lily, it's patriarchal fuckery.
Only fans, while popular for adult content, actually started out as a website for hobbyists, home artists and musicians, etc, as a way for them to connect with fans and raise donations and stuff for their work. I'm guessing this loophole is the only reason it technically doesn't count as solicitation.