He has mentioned on stream that for shipping product he will do D3D.
OpenGL is ugly and unstable on Windows - it is very hard to ship working product for so many bad broken drivers.
On small scale it is doable, when your target audience is a few enthusiasts. But on large scale you will encounter broken drivers and broken Windows installations - testing & maintaining fixes for that is a lot of work and effort.
But - is way easier to start using OpenGL, especially when you are writing your own language. All you need is ability to call C functions, and you can get your triangle on the screen. With D3D it's a bit more work - you need function pointers and structures.
Other than that there is 0 reason to use GL on Windows for serious work. Microsoft recently submitted code to mesa3d which allows to provide OpenGL interface that uses D3D12 as actual backend. I fully expect that this is future of OpenGL on Windows. See https://www.phoronix.com/scan.php...x=Mesa-21.0-Direct3D-12-Gallium3D