to export from opera
I scratched about trying to figure this out but it was quite simple in the end, its easy to export passwords from opera just browse to ‘opera://settings/passwords?search=pass’ then export to your desktop.
to import into Brave
you have to enable the Import option which isn’t on by default go to chrome://flags into your URL bar, then search for “Password import and export.” Set that toggle to enabled and relaunch your browser. Then, head to chrome://settings/passwords (or Menu > Settings > Advanced Settings > Manage Passwords) and the import option is now available