What is complicated about Qt ? You have widgets and events(called signals) , you have clear way to do layouts and powerful ways to extend things. My only complaint is not about the API but is abut C++, when I was working with Qt4 there were not good official or unofficial but stable bindings to memory managed languages.
So personally for a quick side project I don't want to use c++, since is a side project some ugly and slow Electron app will be good enough and if I were on Windows I will probably do a C# Windows form app , or a Java Swing app.