Further troubleshooting...I was seeing the errors below in about:support. I temporarily changed the refresh rates of my dual monitor system to match each other (60hz) and restarted Firefox and now the WebGL stuff was working again. I changed the refresh back to default (75hz, 60hz) and tried to see if it would fail again. Of course it did not, and continued working no matter what combo was used. Go figure.
WEBRENDER_COMPOSITOR
default available
runtime unavailable No DirectComposition usage Blocklisted; failure code NVIDIA_REFRESH_RATE_MIXED
WEBRENDER_PARTIAL
default available
WEBRENDER_SHADER_CACHE
default available
WEBRENDER_OPTIMIZED_SHADERS
default available
WEBRENDER_ANGLE
default available
WEBRENDER_DCOMP_PRESENT
default available
env blocked Monitor refresh rate too high/mixed Blocklisted; failure code NVIDIA_REFRESH_RATE_MIXED
WEBRENDER_SCISSORED_CACHE_CLEARS
default available
WEBGPU
default available
runtime blocked WebGPU cannot be enabled in release or beta Blocklisted; failure code WEBGPU_DISABLE_RELEASE_OR_BETA
WINDOW_OCCLUSION
default available
HW_DECODED_VIDEO_ZERO_COPY
default blocked Blocklisted by gfxInfo
VP8_HW_DECODE
default available
VP9_HW_DECODE
default available
REUSE_DECODER_DEVICE
default available
BACKDROP_FILTER
default available
CANVAS_RENDERER_THREAD
default available
ACCELERATED_CANVAS2D
default disabled Disabled by default Blocklisted; failure code FEATURE_FAILURE_DISABLED