WebGL not on working on Safari on Mac; works on other browsers.

I need some help from the community on getting WebGL to run on Safari on my Mac. I'm running Big Sur 11.6.1 but have had this problem for quite some time. I have confirmed that WebGL is enabled under the Developer - Experimental features list but when I run a test from https://get.webgl.org I get the following error:

Hmm. While your browser seems to support WebGL, it is disabled or unavailable. If possible, please ensure that you are running the latest drivers for your video card.

For more help, please click this link.

The test runs fine on Firefox so it's definitely a Safari problem. In searching the forums, I did find this post from https://discussions.apple.com/thread/251543248?page=2 where VikingOSX gave the following fix.

Pressing the shift key when launching Safari simply prevents it from loading its last saved application state, and does not clear any caches. To do the latter, you [√]Show Develop menu on menu bar from Safari Preferences : Advanced, and then follow that with ⌥⌘E which does clear the browser cache (including cookies).

Safari does write hierarchy into the ~/Library/Containers/com.apple.Safari folder and it you remove that specific Safari folder, and then launch Safari normally, your webgl issue may resolve itself.

Sometimes, Safari writes information into ~/Library/Caches, and provided it is present, removing it from there may provide benefit too.

I did delete anything with com.apple.Safari in ~/Library/Containers; there was nothing in ~/Library/Caches. I also cleared the cache.

Would appreciate any help