after meeting with Sofia at the mall, go to the gas station on Firday and accept her offer to collab and take Mario down, but instead go to Mario to rat her out. BUT I recommend you to sneak her in first to the villa for 2 extra scenes, then after that you can rat her. Once you do, he will give you the key to the guest room where you can use her as your slave all you want.
use this guide:
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all hacking answers are there, as well as routes. in my opinion it is better to not betray Master Zhen so you can share Anna with him, Nyxarra only have 1 scene that is not repeatable, but Master Zhen's is. Also, not betraying Sofia is better as you can have her all you want later, plus 1 extra scene as her reward to you (if you want to keep Emma for yourself, don't share with Mario as well, you can visit her in the sauna once per day after)