Catalina didn’t kill XQuartz, nor did Big Sur. It still works fine, though it hasn’t been updated in 4 years.
It also did not break OpenGL, only deprecate it. macOS is still stuck on a many-years-old version of OpenGL, but what worked in the past continues to work. Even Apple Silicon Macs will support it.
It also did not break OpenGL, only deprecate it. macOS is still stuck on a many-years-old version of OpenGL, but what worked in the past continues to work. Even Apple Silicon Macs will support it.