See browser comparison table here: https://divestos.org/pages/browsers
See browser comparison table here: https://divestos.org/pages/browsers
That's called Factory Reset Protection (FRP). I think most of the mobile brands have it included in these days, Samsung aswell.
uMatrix is no longer maintained. Please see the link:
https://github.com/arkenfox/user.js/wiki/4.1-Extensions#-dont-bother