What would you improve about the primal DMs? They work, but I assume not as nicely as a WhatsApp message?
Discussion
DMs on all clients suck because nostr dms suck.
The most annoying bit is that, even though the contents of DMs are encrypted, everyone knows who I talk to.
Then to make it worse, we have bots spamming you with who messaged who. 
Maybe you can improve it by the following: E.g. Elon messages Jack, but doesnt want the public to know, that he messaged Jack. So Elon posts a note, which got encrypted and posted into a messages-pool. Jack can decrypt the message with a private key. So now Elon basically messages everyone, but only Jack can read it. Now the question remains: How do Elon and Jack exchange the private keys, to decrypt each others messages, without the pulic knowing it? #grownostr
*So with this, the network would at least only know once, that they both have exchanged keys, but not that they continue to exchange messages and when they do so.