I wope up thinking about this exact idea, this is crazy.

But what I was thinking is that nostr message metadata are public, so having all cashu payments come to your inbox might not be great, privacy wise.

Is it possible to have 1 nostr npub that generates sub-npubs, like Bitcoin does with addresses?

So the forwarder (cashu.me) would know the main pubkey but each payment coming to a different address.