I currently use Windows Forms, but I plan to use the Godot game engine in the future. Designing the GUI feels quite similar to WinForms, and I can use C++ or C# (and a bunch of other languages).
I've implemented a DSL for casino slot machine mathematics. I originally did it as an internal DSL with C#, but it was too difficult to use. Many of my customers solve these problems using Microsoft Excel, so a programming style environment is difficult, and embedding into an actual programming language even worse.
I then redid it as an external DSL, which has been successful, but a vast amount of work. A more limited environment has a lot of advantages for my users.
I'm looking at moving my desktop application(s) from Microsoft WinForms to Godot, but its worrying that no one else is doing it yet. It certainly seems appealing, especially compared to the other options, but its not at all clear what the limitations and risks are without investing a lot of time/money into it.
I'm thinking of using godot for the GUI on a decently complex Windows application. I'm concerned that Microsoft is no longer interested in desktop applications and I don't want to embark on something that has no long term future.