i think the monster should be more genshin based, like a hilichurl without it mask can be used for horror and having a face like one of the monster you already have mix with hilichurl would be cool to see. maybe have a bit of a story change like, she trying to find a cure for the hilichurl that have changed in the cave and it give more of a reason to find the items in the cave and to go deeper, it also give a reason why she in a hilichurl camp. if you use more horror version of hilichurl type enemies for the cave would in my mind fit better.
maskless hilichurl to replace the small guy that sucrose sit on.
mitachurls to replace the big guy that fingers sucrose, also for the mitachurls have it fuck sucrose after the finger scene.
you can take and use the ideas i have post as you please. do note i just think genshin would fit better.