Qt is available under LGPL and GPL. What exactly is weird about that?
Up until 2005 or so Qt had indeed a relatively complex licensing scheme where the available (i.e. the license of Qt) and compatible (i.e. the license of the application, due to their GPL exception allowing applications to use MIT, BSD, ...) differed by what was then Qt ports (e.g. Qt/X11, Qt/OSX, Qt/Windows). After that they always had a uniform licensing model for Qt, were the licensing was independent of the platform.
I wanted to like Kivy but it was more clear how to get asyncio support running w/ tkinter. The Kivy folks say they will go to py 3 only soon and support asyncio officially soon but I am in a good place with tkinter.
I am also thinking about a 2-thread architecture which may work well for Kivy since it is so heavily Cythonized.
tkinter specifically does not look very pretty without some effort. I would much rather use GTK or QT. The problem is GTK support on windows is limited, and QT has a weird license model.