Bro, i know it's completely unrelated but stremio now has a android tv version available on the website and its freaking amazing.
Have you tried formatting your flash drive with FAT32. Newer Windows version format flash drive with exFAT by default, which might not be supported by Android TV.
Turn the TV off and unplug from the wall for 2 minutes, has to be at least 2 minutes. Then plug back in and turn on and try again
Go to setting —> apps, show system apps, force close Settings app and try again.
Did you debloat TV? Try power off for some time or reset 🙂
Do android tv devices do formatting? Maybe try format on pc or something first?