This is a good overview of some of the options, but the author’s specific requirements push it in a specific direction that eliminates a lot of options. Specifically, the requirement for completely custom GUI styling without writing his own render functions means it’s really a task of selecting easy, customizable GUI libraries rather than generic GUI work. The requirements to be self-contained executables and under a…
If instead of insisting on custom UI styling the author just used the system UI, they could probably build a pretty straightforward Windows application. It’s the scourge of “brand identity” that has people thinking graphical applications are hard. Same on the Mac: If you want to build a Mac application, your best bet will be AppKit or SwiftUI and using system controls. And when the OS updates your application will ei…
There are exceptions, for very rich dense UI, for UIs that need to be cross-platform, but if you're writing a Windows app, it should look and feel like a Windows app.