https://www.youtube.com/watch?v=dZZuk-AVJzgToday I found an old tool I programmed for a friend some time ago. It can disable the rendering of the environment for multiple 1.12.1 WoW processes completely:
Download link will be published on Zzuk's stuff: [C# / 1.12.1 WoW] Render Disabler today
best regards