We can't do anything else for Galien, I don't want her to be the pirate, it's really bad
Yeah unfortunately the game is 100% linear, you have to make Galien a pirate against her will (along with a LOT of others) if you want to see all the content.
Side note: if you're not interested in lesbian content, it's going to be a very boring storyline as well. As of now there's literally no other (sexual) content available.