@zserv
Unfortunately, there's no known way to 'cure' Android firmware for Garmin devices. Your best approach might be to throw yourself on the tender mercies of Garmin service desk drones. If you get the run-around ask for it to be escalated to a supervisor due to it having been soft-bricked by their software using their own proscribed method. You might get lucky with an even-exchange replacement as it's most likely out of warranty.