Xpra requires a pretty good connection to be a good experience, especially when most of the stuff happens in JS. There’s a WebWorker in use so that some of the data handling is off-loaded into a separate thread, but it doesn’t really solve all of the issues.
But in any case, doing the encryption on the webserver will always be faster when doing it in this context.
Speaking of all of this, I’m actually working on another method of streaming things via Wayland. Stay tuned for that
If you run the Xpra server without SSL and do it in nginx instead, it would have the same effect, but faster because no JS.