since you think she should get nothing from both spotify and onlyfans

I don't know where you got that "both" from.

Regular people don't get royalties for their work either. Factory workers who assemble ovens don't get a cut from each meal a restaurant cooks, for example. Those filthy rich musicians, Hollywood actors, etc. keep leaving out that they've already been paid millions for their work. They leave out that they sold the publishing rights to record companies. They act as if they earned less than you and me. They are doing absolutely fine. No need to fight for a right to better royalties or anything like that. If they need more money, they can just make new music.