lovefromisrael What do you mean by "paste password from password manager" ?
Regarding bitwarden specifically, I once found these instructions (that worked for me) to have a fully integrated bitwarden experience within brave :
Go to: brave://flags
search for "Enable the setting to provide a virtual view structure for Autofill" and enable it with the option "enabled without any compatibility check".
Restart the browser (best would be to force quit).
A new menu should appear in settings below " Downloads" called "Autofill Services"
in that menu, select "other providers"
restart browser again