I'm not sure what setting in brave caused this, but brave will not allow bootloader unlocking. You'll be tripped with a device not found error, if I remember the error correctly. This may be old news and I'm late to the party, but i figured I'd post if not.

Thanks for all your hard work.

    Lolsrslybro Please try disabling Brave Shields for the site, and make sure you did the OS-specific instructions such as udev rules on Linux and installing the fastboot driver on Windows. Android, ChromeOS and macOS don't need anything special.