From what I can read of AVX-512, it's a bit of a cluster. Issues with the frequency hit on the whole processor speed just for dipping into the AVX code, as well as the problem of it being included in some CPUs but not others of similar lines. I don't know much more than that, but seems like some (most?) developers aren't too happy about the situation.
Yeah hardly anyone adopted AVX-512 and Intel has mainly been using it to artificially score better in benchmarks and to appear to have a higher stable frequency until the hit from using AVX-512. And then there's the excessive heat. With Alder Lake though, it's going to be a clusterf*ck because some of the cores on those CPUs will be regular cores while others will be Atom cores. AFAIK there will be no HT and i wish good luck on an OS trying to schedule tasks properly because of the decreased capabilities of Atom. Will be many bugs to work out, i'm sure.
Prime hunting adopts AVX-512.
4000 MHz RAM will be optimal this time it looks like