NosDAV could be a useful addition. I like Gun, but I have found it can be resource intensive sometimes, and hard to debug why.
Ultimately, nostr can interface into many different persistence mechanisms, with just a pointer on the relays.
I don't like new event kinds. They make building a nostr client more difficult.
I'd like to build a gundb-like universal database on Nostr where you write to filesystem-like paths such as group/[id]/messages or group/[id]/name instead of defining new event kinds for everything that could expressed as a path. https://github.com/gundb/gun
Nostr is not going to be an "everything app" if you need new event kinds for everything.
I'm quite busy improving the very basic features of Iris, but I'll try to find time for it at some point.
Discussion
I'll take a look.
GunDB is a great idea, but the implementation was very difficult to work with when something didn't work and you had to look under the hood.
Also the protocol was such that making your own implementation was quite difficult. But definitely the concept is good.