In the latest iteration, they removed AVX-512 iirc. So was there even as window when it worked well and shipped on a majority of new CPUs?

No, but that's mainly because Intel has been totally incompetent for the last half decade. On Zen4/Intel chips post 2020 that have it, AVX-512 is really good.

No, 512 still fries skylake.

Read my comment again

I did, still can't figure out what you mean by "chinese whispers from processors"

Oh, we call that game "deaf phone" (in loose translation) here.

I knew many project managers that played it...