The amount of backend stuff for various systems that Nostr can improve is immense.

Decentralized social media is a big deal, but that use case goes up against very large existing network effects. If you judge Nostr’s success based on not gaining traction on that front quickly enough, you’ll likely be disappointed. That’s why a lot of people come to Nostr, post a bit, and then leave for a while, and then come back when there’s some sort of catalyst, post a bit, and then leave again. That’s fine. It’ll take time. It’s a slow burn.

But in the meantime, the amount of development going on under the hood for all sorts of things is huge. In particular, I think the open-source social graph aspect is under-appreciated for how important it can be beyond just socials. Payments being the next obvious one, and probably bigger than people think. And many other things.
https://pippellia.com/pippellia/Social+Graph/Navigating+the+social+graph