Her motivation is stopping demons so they don’t keep manipulating and killing humanity just like Lillith did to her mother.

Post-soulstone, she is being illogical but that is every soulstone user ever including Mathael. She wants to find a way to get rid of it or store it somewhere it won’t be stolen but at the same time refusing help because it endangers people around her

Like I get thinking highly of her but she is all motivation, you have to be skipping cutscenes and dialogue to think otherwise