Using bitwarden, it adds them in just fine. But, if you go and try to log into a Google account with Brave, it tries to use the Brave system builtin instead of the Bitwarden one. Presenting a dialog too.
As an end user, I don't know if it is bitwarden, brave or google screwing this up and I can't be bothered to figure it out, so it is back to just using passwords and 2FA...