I will still place my bet for C++ combined with a third party UI Framework. I know that Qt has changed its license model, but it offers many capabilities and is battle-tested enough.

Otherwise another shot could be a Java/JavaFX application, possibility compiled natively or packaged with jpackage, so you deliver your own tailored JVM, without requiring the installation of a JRE on the user system.

Another way would be to embrace the Microsoft ecosystem with the Windows UI Frameworks and then use C# or C++