An interesting comparison is K-Pop singers who are at the same time megastars with millions of devoted followers, but also carefully managed to always seem available for a relationship. A truly difficult bridge to cross, but they somehow do it and make bank.
Parasocial relationships are not bad per se. Let's say you are thinking about Donald Knuth when working on a computer science problem, nothing bad here, taking inspiration from the leaders in the field. But it is also a parasocial relationship, it is like imagining Don Knuth next to you, helping you solve your problem, even though he has absolutely no idea about who you are. It is a one way connection, but here, it is actually productive.
If you’re ignoring the “believe you have a two way relationship” then everything could be defined as parasocial.
To a degree it’s also quite normal to have parasocial reactions to personaes from media, it only becomes problematic once people substitute actual social relationships with extreme parasocial relationships.
The closest equivalent you would get with a movie is to send fan-mail and get a response. Which people do, but I think it's safe to claim the frequency is much lower.
If you feel a strong connection to a character and they barely know anything about you (or barely feel anything towards you), that's not truly social.
More live TV/streaming series than movies, IMHO.
How many times have you heard someone say they just finished watching $SERIES and will miss their TV friends?
And with OnlyFans (I'm guessing here, as I don't use the platform), at least the sexual stuff there (is there other stuff?) it's like going to a strip club, except it's all recorded (and sometimes? mostly? more explicit) and instead of dollar bills in the garters, it's tips/subscriptions.
Whether it's more or less parasocial than live streaming has more to do with quantity and access than it does the specific form of media.