I think the problem of Mobile OS is, that most official apps (administrations, banking, etc) are only for Android or for OS with Google layers. Because of this (I can’t use other OS than Android on my very basic phone) I don’t use my phone for more than for basic tasks (calls, messages, some OpenSource games from F-Droid…) without any important data stored (also GPS desactivated). Mobile phones generally are not secure or private, very prone to loss, theft or being intercepted, especially in frequent use in public WiFi LinageOS is a valid alternative like other more private distros, but the real risk is the user himself and how and for what he use the Phone