I have a Lenovo K5 Play, it's got it's own rendition of the Android OS, it's basically a skin so anyone who see the GUI for the first time, think I'm using another OS entirely, until they go into the inner workings of the phone. I don't know if it has a Safe Mode though thankfully I practice healthy habits with my system and phone.
Agreed, that phone might need the tactical approach and probably a reprimanding to the person who had the phone.
Good luck on the steps you're taking from here on out!