I haven’t found this to be the case in practice (IE passkeys are plenty portable). I’ve successfully used passkeys on multiple browsers, OS’s, and apps, all stored using a FOSS password manager (keepass). Any FOSS password manager that is either self-hosted, or syncs, should work just as well with passkeys as it does for regular passwords or TOTP.
I haven’t found this to be the case in practice (IE passkeys are plenty portable). I’ve successfully used passkeys on multiple browsers, OS’s, and apps, all stored using a FOSS password manager (keepass). Any FOSS password manager that is either self-hosted, or syncs, should work just as well with passkeys as it does for regular passwords or TOTP.