Hey there. Just had the same problem today. After updating snap version of brave into 0.57.x the client which was used with root gives out an error. On my machine it was mkdir error.
To fix this, just install brave with those instructions https://brave-browser.readthedocs.io/en/latest/installing-brave.html#linux, then import all bookmarks from brave old in the bookmarks settings and you are free to use the new version. Everything is explained better under this topic: Brave forgets EVERYthing after update. Working as intended?
Hope this will help you,
Cheers.