We use this a bunch for writing rpc protocols on iroh: https://github.com/n0-computer/irpc , but there's no reason you couldn't write one with grpc.

Also, AFAIK, Iroh makes some architectural choices (using relays to help establish connections), that make it less "pure p2p", but much more likely to actually work reliably.

Many existing iroh protocols have clear client and server roles once the connection is established. E.g. gossip is a peer to peer protocol, blobs is a client server protocol in that one side provides data and the other requests it.

For a client you can use an ephemeral node id and not publish your info to discovery, since you will never be dialed yourself.