https://github.com/0xchat-app states it doesn't have desktop clients.

Also, the direct messages have three types

1) NIP-04 DM: "Most widely used", but also, "not recommended". Reeks of Telegram that also has non-secret chats being the most popular option

2) Gift-Wrapped DM: Uses different encryption algorithm but no forward secrecy? Forward secrecy has been around for 20 years.

3) Secret DM: Can't be recovered on different devices. Why can't the backup be self-contained database like Signal has?

Also "Secret chat requires consent from peer." Like what :D You have to wait for contact's approval to have a private conversation with them. Sounds like it incentivizes all chats to start with less secure protocols.

The nice part about writing your own chat system is the security agility in that you can bump any security property without having to fight with protocol standardization bodies. Having three DM protocols inside the same app is wild.