Currently, data like passwords, usernames and totp codes are only copied to the CLIPBOARD clipboard of X11, however I would argue it should be copied to the PRIMARY clipboard aswell (see this article for details Clipboard - ArchWiki).
This would allow the user to paste data usind their mouse, which makes more sense if they just used the mouse to click the copy button, thus removing the need to move yor hands between mouse and keyboard and streamlining g the whole process.