Decentralizing everything doesn't scale well. Instead of doing that, look at how Minecraft does it. Decentralize at the server level, not client device level. Each node should be someone's Linux computer plugged in beside their router, not someone's phone.
Minecraft is successfully decentralized, except for the identity service. When you buy Minecraft, you're actually buying the right to register an account. You could just copy what Minecraft does, but add a decentralized identity service plus some anti-censorship measures. Don't touch cryptocurrencies at all, it has a bad reputation due to scams and you will lose to mainstream competitors just because of that. Take ideas from Nostr but stay away from Bitcoin. I like the idea behind crypto but it should be a separate project, not embedded in the messenger.
Give it a polished cross-platform app UI/UX on par with Discord. Do the development entirely anonymously so that you can't be sued. Open-source both the client and server. Make your binaries reproducible so that people can verify there's no backdoor.
And to combat censorship, wrap all traffic in HTTPS and add NAT traversal like SoftEther VPN. Use a decentralized compact routing scheme like Yggdrasil Network to replace IPv4/v6, and add onion routing between servers. That will make it nearly impossible to geolocate servers and the traffic will permeate everywhere as if all firewalls don't exist.
The result is an app like Discord, where people can host their own servers like Minecraft but better because there's no need to port-forward (and each server is an actual Linux server/computer/VM), that is impossible to censor even for nation states. And if you add a Nostr-like protocol for passing global messages between servers, it could replace Twitter/X as well.