The Xiaomi Android One line-up was unlockable without any hassle, but is long time discontinued. I used to use the Mi A2 lite as my main phone and you could just unlock it yourself offline. Only thing blocking you from doing it was the OEM unlocking toggle in developer settings. I still have the phone and it is running Android 14 like a charm.
I actually found Cinnamon to be more resource intensive than Gnome on most computers.