I ran with just RenderTexturesSingleThread=1 and just RenderSingle=1 and then both and got the OpenGL error all three times.
For my most recent run I added 'GLListDebug=1' and disabled Tree LOD (I hadn't tried using HD Tree for any of the runs) and it generated fine. Screenshot of my settings that worked, and error logs attached.
Logs:
https://ufile.io/fq6v9273
Texgen Options:
https://ufile.io/sc1lfaup