Why not simply installing lineageos or AOSP instead?
Because it is a lot of work, not all phones support/allow rooting, you need to hide root for apps manually for them to work and there's no way to take full backups on Android phone, rooted or not (adb backup is deprecated and never actually worked at all anyway). Meaning: every time you screw up (or get a new phone) you have to start all over, without the ability to restore a backup. This can easily take many days wo…
> there's no way to take full backups on Android phone, rooted or not
Er, no? On the contrary, root is exactly how you get full backups on Android - with, I grant, the exception of whatever Android calls their secure element / TPM, which I've only ever seen affect 2FA apps.