Comment by rollcat

I'm no UX expert, but I regularly try out new (and old) toolkits to understand the problem space.

It really sounds like you want an immediate mode toolkit. Retained mode will never be "super-snappy", there's an entire sandwich between your code and the pixels. Look at Blender or Reaper, this is the kind of "feel" you'd be getting.

If you want retained mode + "true" native widgets on all platforms, investigate: Toga (Python), WxWidgets (C++), and Tk (Tcl). The native toolkits are often best in class on each platform, and these wrappers are about as thin as they can reasonably get (e.g. Toga uses pyobjc). Integration with Rust is left as an exercise to the reader ;)

A rich widget library is nice, but consider the depth as well. Egui went to great lengths to integrate assistive technologies, which depending on your target audience may be impactful. (Also: accessibility is for everyone. https://shortcat.app/)

If you want easy hiring, you have to go with mainstream. We've +/- named all of the options by now. Otherwise, hire a talent who's worked on the next closest thing to what you're building, and trust them to decide the direction.

Looks and beauty are in the eye of the beholder. There are many apps that have a distinct, sometimes quirky, but appreciable style. Reaper looks out of place on every platform, but I prefer it over Logic or Ableton.