This is a good overview of some of the options, but the author’s specific requirements push it in a specific direction that eliminates a lot of options. Specifically, the requirement for completely custom GUI styling without writing his own render functions means it’s really a task of selecting easy, customizable GUI libraries rather than generic GUI work. The requirements to be self-contained executables and under a…
The blogger sounds like they put up a bunch of arbitrary constraints that in normal circumstances wouldn't even be issues.
In the process it's those arbitrary whimsical choices that reject the very obvious choices along with any happy path.
For example, it's baffling that there are already a few FLOSS forks of Qt out there, but the blogger failed to cover them. If the author likes Qt so much, those would supposedly be the obvious choices. But no.
Once again, you are left out of options if you go out of your way to avoid each and any option.