JavaFX isn't hard to learn. In fact, any developer with a little bit of object-oriented knowledge and a penchant for desktop development in Java can quickly put together a feature-rich GUI application ...
An example of how to use MVVM (UMG ViewModel plugin) with your UI inside Unreal Engine. Project is build on UE5.4.4 This example heavily relies on using MVVM only via C++, instead of setting in UMG ...