Sysadmin

Not as the only way but using paperkey might be a good idea too.

I install my keys on 5 Yubikeys and then encrypt a copy of the private key so that it can only be decrypted with one of the Yubikeys. I store the encrypted bundle on Google drive and I’ve spread out the Yubikeys a little geographically by sending them to friends who I trust (PIN is still required to use the Yubikey so there’s still a layer of security). I also keep one of them in a safe at my house just in case.

I do feel like I may have gone a little overboard but maybe something similar could work for you!

I have mine in a Kleopatra keychain for convenience, but I also keep backups in a KeePassXC encrypted database for security. They are essentially text files, so you can treat them the same way as you treat your passwords. I hope this helps.

I mostly just use personal pgp keys now, but I keep them in an encrypted container on my external hard drive and in proton drive.