Why did she keep her alive? No really. She fucking uses MINDMAGIC! MINDFUCK! You can't trust anything she is telling you. That one time in this chapter, when MC said, she isn't even mad at her, can she be so sure, that Venus didn't just use her brainwashing skill again? Who's going to believe the "I can manipulate memories, but it happens, that your awesome mind is to strong for that" BS?
At this point the MC can't even be sure anymore, that a place like "Earth" and computers are even existing. It might just be something Venus came up with to brainwash her into believing, she's a dude from another reality, while she indeed is the real deal, and that there is the only real reality.
That's the bad thing about mindfuck magic in stories. If you use it without giving really STRONG restrictions it's a story destroying ability and the story falls apart.