Nostr lacks decentralized discovery, although with some open mindedness it can be added easily, and I did some work to prove it can scale (120,000 users records kept alive on Bittorrent DHT with one 4cores vps) see more at github.com/nuhvi/pkarr

But I am curious, if you do have decentralized identity with Pkarr, and you can add that to Matrix protocol, to patch the need for identity servers, what else is going to be missing from Marrix, it is also signed events protocol, but with a lot of time to mature and state of the art encrypted chat rooms with moderation and access control.

What is your best argument against Matrix? Also how long can Nostr stay simpler than Matrix if it is going to have all these features you mentioned?