It is hard to get the absolute best performance out of OpenGL but it isn't really hard to get good performance. Unless you're trying to make some sort of seamle

It is hard to get the absolute best performance out of OpenGL but it isn't really hard to get good performance. Unless you're trying to make some sort of seamless open world game with modern AAA level of visual fidelity or trying to do something very out of the ordinary, OpenGL is fine. A bigger issue you may face is OpenGL driver bugs but AFAIK the main culprit here was AMD and a couple of years ago they improved their OpenGL driver to be much better. Also at this point OpenGL still has no hardware raytracing extension/API so if you need that you need to use Vulkan (either just for the RT bits with OpenGL interop or switching to it completely). My own 3D engine uses OpenGL and while the performance is perfectly fine, i'm considering switching to Vulkan at some point in the future to have raytracing support.