I actually agree with all the points you're making but you're never going to get people to agree with you or get anything changed with inane incel wording you use.
I think her willingness to have threesomes/foursomes comes completely out of left field and contradictory to everything in her romance. She won't sleep with you act 3 seemingly because you need to build trust with her but suddenly she's willing to do group sex? It makes zero sense whatsoever. The guy who wrote Shadowheart also wrote Halsin so it leads me to believe he's just a self-insert for him and that's why she's so willing to do. And because of the fact that Halsin reads as a self-insert I don't consider anything involving the two of them to be part of Shadowheart's character. It's just weird shit this guy put in the game for himself which is a shame writer's shouldn't do that.