Check at the URL opera://settings/handlers. You might have mail.google.com set as the default for mailto links in Opera. If so, you should be able to remove that handler.
@brandonknowt still shows theres an update, and to restart opera to install said update, but doesn't update. but i think its just a flatpak issue, as it still shows version behind on there. using silverblue, so installing the package is just to extra and prolly just stick to the flatpak or decide silverblue isn't right for me lol