I resent that I need a special app to "manage" them. I want to know where this key is on my filesystem so I can back it up and edit it myself, not have to use some app to access it. My ssh authorized_keys is just a text file. I can "manage" it with something as simple as vim. Maybe KeePassXC and BitWarden give you that simplicity, if so great!
KeepassXC gave users this choice. And was threatened to be blocked for it.[1]
[1] https://github.com/keepassxreboot/keepassxc/issues/10407#iss...
KeePassXC "supports passkeys" but the website/app that offers the passkey needs to offer it in the correct way for KeePassXC to ingest it. I've found a fair amount of scenarios where they don't correctly let you drop it into them.