I've recently discovered FLTK: https://www.fltk.org/doc-1.4/intro.html

Haven't used Qt in a while, but at first glance, seems simpler: https://github.com/fltk/fltk/blob/master/examples/menubar-ad...

FLTK is great at being fast and light, that’s about it. It’s kind of cumbersome to use but honestly does what it says on the tin. Highly recommend for smaller use cases but can’t imagine using on a large project. I used the rust bindings which are well maintained.