Hi Peter,
I primarily run Processing on Mac. Processing is available for Mac, Windows, Linux, and Raspberry Pi – you can see some of the downloads on the official downloads page:
https://processing.org/download/
My impression – just an impression – is that as of today Processing currently runs best on MacOS 10.12–10.14 or Windows 7-10. We’ve seen some new problems with MacOS 10.15, particularly with cameras and video. My main machine is currently 10.12, but I also use it on 10.14.
However we have lots of Windows users around the world. Many thousands at least at any given time, including students. To the best of my knowledge they aren’t all having the problem that you are with 3D OpenGL.