Yep, Apple solves this by moving FIDO key material around via iCloud, I believe. But it requires a good syncing mechanism like that. In principle it's similar

Yep, Apple solves this by moving FIDO key material around via iCloud, I believe. But it requires a good syncing mechanism like that. In principle it's similar to the password manager problem, which is a bit ironic: if everyone used password managers, most of the same security issues would be resolved. (There are a few cases where a FIDO key is better than a password manager, but not many!)