Well the thing is it seems to only affect every other mac user even with otherwise identical hardware and os version.
If I had to guess I would chalk it up to a qc issue on some Apple specific chipset that just doesn't get hit by the other browsers code paths and just doesn't get noticed in other less used, less intensive apps.
How to diagnose it or work around it is beyond me.
Don’t you think it’s more likely there is a bug in macOS-specific Firefox code?