I am a some-what experienced programer, and I have been working on creating a 3D graphics engine utilizing the OpenGL system, primarily focused on use in games. However, I also want to do some work with functional programming, and wanted to create a clean UI for more functional programs, like a task manager. An example of the kind of effect that I want to create could be somewhat like the Visual Studio Code UI. My question is: is there a specific library that I should use for creating desktop programs, or should I continue to use OpenGL's 3D aspects, but keep everything in a single Z axis plane, effectively creating a 2D program? Or is there a better way to create normal program visuals, that wont be cheating out of a 3D graphical space?
Thanks for your help.
EDIT: I am currently using C++/C, but I am also happy to expand my knowledge base to include new languages.