I am running Linux Mint 21.3 and using it as a kiosk for guests. I installed via the linux mint repo (Flatpack) and it booted/worked fine under the admin user. When I log out and switch to the guest user brave will not launch.
I then uninstalled it and installed brave via the website. Still when using guest brave will not launch.
All I did was enable guest mode (Settings → Login WIndow → Users → Allow Guest Sessions) to cause this. Have not tried in other distros.