I've spent about a month now researching how to run OpenGL with hardware acceleration on a Pi 4 and I'm very pleased with the results. The challenge was I wanted to use C# as it is a much friendlier language than C++ and I also wanted to write common code that would run on either a PC or a Pi. Using .Net Core means you can compile and test on a PC using the free version of Visual Studio and then just copy the compiled program over to the Pi and run it there.
Here is the result: https://youtu.be/OK4HFYUz02w
and here is an earlier test with a side by side comparison: https://youtu.be/zDaMoG3RvK0
I worked my way up from drawing a triangle on the Pi in C. I wanted to understand everything from first prinicples and also needed to learn OpenGL at the same time so it's been a slog but very satisfying. The Raspberry Pi never ceases to amaze me!