The 2nd one isn't exploited because they're not having any surplus extracted; and they're also not neccessarily producing value either, because what they're selling is a digital commodity that requires (essentially) no labour to reproduce. It's intellectual property essentially. However, if they're providing a service such as a camshow, it's a different thing.
They're definitely not employed in a wage labour relationship, so they're more like a small producer or self-employed.
Really it depends on what they're actually doing. Selling nudes on Twitter/Insta/etc in the DMs, you're not being exploited; paying a subscription fee for a service such as only fans is much more complicated since that platform itself is utilizing a rent-extraction mechanism, but they're not really exploiting the seller as much as they're "taxing" the buyer. It all depends on access really, at a certain point with these relations (which don't just apply to Sex Work btw, but to all of this "gig economy", "contract", "crowdfunded" shit etc) if the platforms have a legal monopoly approved by the state to host a marketplace for the content then you could argue that they're employers and are exploiting people in a sort of distorted piecemeal wage system but really it's just a wealth transfer system between workers.
Different kinds of sex workers have different class interests but the term sex worker is used by activists and lobbyists to attempt to flatten the distinctions. Someone like say, Stoya, who is Petit-Bourgeois doesn't really have the same interests as an e-girl who sells nudes part-time to make up for the deficit she receives in starvation wages, in much the same way an uber driver also works another job. Yet, we're told that all sex workers must fight together for liberation and yet in a class society who controls the narrative and means for said liberation? It's going to be the ones who have ties to the firms looking to profit and proletarianize sex work in a more regulated manner. Do we want an Uber for Sex Work? Probably not, so then whilst decriminilization is an obvious neccessity, if we're talking about legalization we need to ensure that we combat what is essentially a class collaborationist narrative attempting to marketize and atomize people even further. There are lots of questions there though.