If you like using Qt but you also want a more modernize C++ version of it, you can try https://github.com/copperspice/copperspice/ and I'm pretty sure its license have you covered.
The folks behind that framework also have an amazing Youtube channel [0] where they talk about complicated C++ topics in great clarity (well, as great as one can expect for such a complicated language). They don't post often, but when they do, it's almost always a gem.