How much effect the CPU's register remapping has? Probably a lot and the article doesn't discuss it at all.

However, the Intel Xeon E-2236 was released in 2019; so it's hardly ancient and the current E-2400 isn't so different.

As for hardware register renaming, Tomasulo dates to 1967 and out-of-order ROBs were common in the 90s. I don't know that there's been any major new ideas microarchitectural ideas in register renaming since the 90s.

I still think it's a meaningful experiment but could be improved with consideration of microarchitectural features.