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’d be interested in that!