if you want multiple identities you can create multiple npubs. plus, i think it's fine to signal on the fediverse that your profile is a bridged nostr profile.
And if you want to participate on both the Fediverse and Nostr you can have a Mastodon account and a Nostr npub.
The fact that multiple identities require multiple account is a clear design flaw of NIP-05.
The fact that multiple identities require multiple account is a clear design flaw of NIP-05.