I remember reading somewhere that Godot is what Tesla uses for the app of their cars. Don't quote me on that one, though.

EDIT: https://news.ycombinator.com/item?id=30627087

PS: I cannot confirm the veracity of the link I post.

It builds to cross-platform pretty easily so that is a big bonus. Godot supports C# as well and its own scripting language but not much else. You won't be able to take advantage of native UI elements, but I don't think people care about that as much anymore.

The built-in development environment is mostly non-negotiable (you can supply your own IDE for text editing but thats it) but its well designed and is made to work with its component model. It feels fun to use. The data model also works better with source control than other game engines, but not as well as non-game UI toolkits. If you're a text-environment purist, you might be turned off, but you'd also be turned off by all the big game engines.

I've met developers who use Unity to make mobile apps since the built-in 3D compositing actually makes some applications more performant than the native toolkits. I'd imagine Godot would have similar benefits.

From having tinkered with it before and also from using the Godot editor (which is itself made with Godot), it does seem viable (and even quite pleasant), however it’s worth noting that it’s unlikely to have Qt’s level of accessibility support (eg screen readers) since that’s not typically a focus of graphical games.

The most full-fledged GUI app I can think of in Godot is RPG in a Box (https://www.rpginabox.com), itself a game creation toolkit. Its UI is decent (and IMO a lot more attractive than a lot of cross-platform toolkits I've seen), though there's a lot of very obviously non-native elements and quirks.

Are you thinking of something like this? https://git.sr.ht/~sircmpwn/gdwlroots

If you want to see what an "ideal" godot GUI is like, just download the godot editor. The editor itself is a godot app.