Once in TWRP, you must format data (factory reset) to remove Samsung's encryption.
The first boot takes a while, but once the Magisk app appears, you're officially "Superuser." ⚠️ Words of Wisdom Once in TWRP, you must format data (factory
Go to Developer Options and toggle OEM Unlock . If it’s not there, you may need to wait 7 days (RMM State Lock). Once in TWRP