It's a general problem with public key cryptography, not just physical security keys but also SSH keys, wallets, etc. You should try to use a single key pair fo

It's a general problem with public key cryptography, not just physical security keys but also SSH keys, wallets, etc. You should try to use a single key pair for everything as much as you can. I understand the laptop case where you want convenience, but I assume that's 1 laptop = 1 company. For all others, you should probably attempt to use a single key for everything. Note that in FIDO, unlike general public key crypto, there's unlinkability built in. If you use the same key on different accounts, there's no way for the service(s) to tell if it's the same key or different ones. This is to say that privacy is built in. FWIW for solokeys we made colored silicon cases and some people have used colors successfully to identify the keys. Yubico did stickers (not sure if you can buy them, but you can certainly print your own). But in general I doubt there's a good solution.