Sometime ago I did lowent.xyz which is more or less what you described 🤝
#Nostr Shower 🚿 Idea 💡
A Nostr Client that encrypts all notes and the notes can only be decrypted using said client
All relays and other clients would see encrypted gibberish
nostr:npub1kpc36kmttp0whcxcq05wmzqndsmprkrhcd8gxsp5ln9nkaxvr0nqdtytxp nostr:npub1sg6plzptd64u62a878hep2kev88swjh3tw00gjsfl8f237lmu63q0uf63m nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft
nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z
#asknostr
There are times, when I really wished, I learned how to code
this is one of those times
Discussion
as #nostr gets more permanent and popular, we will need this type of client functionality