Xiaomi Redmi phones
Xiaomi Redmi phones have such a messed up Android... That HyperOS crap they put in it has the worst memory management I've ever seen, and I'm a Software Engineer! It looks literally like everything is always on an urge to throw away used RAM! If you have to use stuff like Google Authenticator for 2FA and you need to step out of your app for like 5s, when you get back, the memory is gone and here we go again from the start! Sometimes it releases the memory even when the app is minimized by accident... When you pull it back up, it's gone! Setting battery saving to "unrestricted" or using Performance mode doesn't make a noticeable difference either! That thing is barely usable, and you should stay away from it until they fix it!