I mean no offense to the egui people because they have done amazing work, but it isn't that it isn't native, it is that it doesn't look good enough to ship something with it (other than a science/medical/gaming UI perhaps, but certainly not a business app). Gtk won't look native either on anything but Linux...at all, but at least is very professional looking in its default theme. Obviously what looks "good enough" is highly subjective.
UPDATE: True, it is themable, I just wish the default was a little more polished
You can skin it fully though. I have an app that looks nothing like the default theme. Customize it to your taste.
Note: I did have to implement some missing features for my purpose, so when I say “fully” I mean I had to spend a couple hours putting the features I wanted together. But in the end, it was a great result. Maybe this work should be turned into a PR, I dunno.
I still think the webview thing will be a long time coming if that is something you absolutely need. Best bet is probably something that renders the output of a web engine to gl to stuff in an eguingl window.
I've used such horribly themed business guis that my expectations are probably very skewed. If there are buttons and text windows, and neither of them move when I try to select them, I'll survive. My only explanation is kickbacks to the person that selected their purchase. The worst is when the text entry fields silently sanitize things sent to the server so you don't actually know what went into the database. Well, I guess the worst is that it didn't sanitize the entry at all and some of the characters had special meaning to the ancient backend...
UPDATE: True, it is themable, I just wish the default was a little more polished