Egui is pretty bad idea. It uses "immediate mode" rendering which means whole window is redrawn on every mouse move. I ran PhotoCraft (built in Rust + egui) in a VM wihout a GPU and the UI felt like it was running on 3 fps.

Egui is definitely not what you want to use on a 4K screen. It is only good for tiny screens of embedded devices.

Why there is no reactive UI that tracks all dependencies and redraws only what needs to be redrawn? (not React, it also re-calculates (but not redraws) everything on every change).

Also why does it visually look like bad version of Telegram?