Adam Williamson wrote:
Also, these days, most authenticator apps support some kind of backup mechanism. FreeOTP lets you back up to a file (which you should, of course, keep somewhere safe and ideally encrypted). Google Authenticator can backup To The Cloud.
If you use Keysmith, you can just SFTP your ~/.config/org.kde.keysmith/Keysmith.conf from/to all your GNU/Linux computers including the PinePhone or equivalent, and they will all be able to generate the same TOTP keys with the same master key.
Kevin Kofler