I'm not sure I can help because I have only access at Wayland in a VM machine hosted by macOS.

I would suggest to try first with a very simple GL app, say FLTK's test/shape and without CMake,

without installed, shared FLTK libs. Just use fltk-config and a non-installed, static, debug-ready

version of libfltk. Can you determine a list of Ubuntu packages and link command switches

that produce an executable using NVidia's EGL lib? Then, Albrecht should be able to tell you how

to get the same result using CMake to build a full size FLTK client app.