Maybe this? Although it happens to you even on startup, so it’s very unlikely.
Or starting Brave as an administrator just to be complete?
Try this solution again and make sure the link matches the one on the picture?
Are you willing to loose your BAT for trying a full reinstall? (And keep a backup of the old files to try to retrieve the wallet later somehow)
I am not part of the Brave team, just trying to help.
Maybe @steeven knows more? I didn’t find an issue on GitHub or something we haven’t tried on this forum.