I think the main confusion is because the extension always needs some sort of lightning "wallet" and that then can have a local key that is used for nostr. (and keys are only locally stored and a wallet is always some remote wallet)
this means you can add the same wallet to the extension and use this same wallet with different keys.
you don't need to create a different alby accounts or different wallets.
nostr:npub1raustrrh5gjwt03zdj8syn9vmt2dwsv9t467m8c3gua636uxu89svgdees I will pass it on.