I currently use Authy on my android and my Linux system.
It syncs every new authenticator between my devices but I dont want to trust companies with my security anymore.
I host a nextcloud instance on my homelab. Does anyone know a good FOSS authenticator that can use my nextcloud to sync between Linux and android? Provided that it is available on both of course.
Personally I would use andOTP on my mobile with backups and use OTPClient on my computer. I don't like having my 2 factor auth stored in the same system as my passwords. Because if the password manager was ever lost or stolen you'd have all your eggs in one basket essentially.
andOTP is no longer maintained, so it's not a good suggestion and you should probably see about migrating to another app. I personally went to Aegis and had a smooth transition.
While that is true, there have been many discussions about if there are any known security vulnerabilities or new spec changes that would cause a problem. The consensus from the community is that it is safe to use for quite some time. Not invalidating your points in any way just putting out what I know.