Secure backup of 2FA seeds.

I have a 2FA generator set up on my primary Android phone and I want to be able to securely push backups to my Linux desktop and another Android device whenever I add or remove any keys. I thought about using Syncthing as a delivery method, (what are your thoughts on that btw?), but there's a problem with the client itself. FreeOTP+ I'm using right now exports keys in plain-text .json which of course is a no-go. Any advice is …

2fa backup privacy