I think… “knockoffs” are pirate CPU unofficial without patente licenses, and ARM don’t run X86 conventional programs, so the only companies that rightfully manufacture X86 CPU are intel, amd and via tech.
amd also include some harmful technologies and the architecture is worse compared to intel, via tech doesn’t offer a high performance processor, and the architecture is worse than amd.
I think intel currently the only that purism can use, and only on 5th generation backwards because exist a blob on newer CPUS (i915 DRM), outside intel, amd is the second option, but intel is more desirable.
sorry if my English is bad, I’m not a fluent speaker.