Writing a good encrypted chat app is very complicated, even if it may seem very simple. Message threads are a simple concept but they quickly complicate UI flow and program design, especially when you can’t just ask the server “give me all the messages in this thread” because of encryption. Writing end to end encrypted messengers is hard enough already, but adding federation between servers to the mix makes it almost impossible. There’s a reason there are basically two federated, E2EE chat standard (XMPP and Matrix) and why nobody seems to be using either of them.

It should be noted that Element X isn’t finished yet. It’s basically a public beta. When it’s ready, it’ll be called Element and replace the old app.

Cinny and many other Matrix clients only implement parts of the Matrix spec (especially verification). The only fully compliant web client I know is Element, and on desktop there are a few that come close. Threads are a relatively new feature that doesn’t work in most clients because they require design effort to support. Fluffychat and Cinny in general look nice, but in terms of feature support they’re actually quite barebones, and development isn’t as fast as with commercial chat apps.

If you want the full Matrix experience, stick to Element. It’s the only application with actual funding behind it, and the only implementation that actually has the features Matrix is capable of supporting.

Not being able to load old messages seems to be a symptom of a slow server plus messages not having been downloaded to your device before. Recent additions such as Sliding Sync have improved responsiveness for new users and devices, but for old messages you’ll still need to sync all the way back, and that can be quite algorithmically complex, especially in encrypted rooms. Servers also seem to be written so that new messages are delivered fast, not to make browsing the history faster, which makes sense because that’s how most people use chat apps. State compression on the server side can help with speed, but will only do so much if the server itself is overloaded.

All in all, the Matrix ecosystem is full of quick, throwaway projects, led by an underfunded company that is struggling to keep its own applications and server running well. If every Matrix user would donate a dollar a month, I think the ecosystem would be much better, but right now it’s struggling to keep up with its own development.