PS/2 Keyboards are faster than a USB keyboard with slow-speed negotiation with the host computer but for USB keyboards with high speed negotiation, they are at par[1]
>if you actually measure time from keypress to event
Nobody measures keyboard latency this way because when you do the keyboards with less key-travel (Apple Magic) end up with lower "latency"; clearly an absurd result and not at all what you are actually trying to measure. It does not line up with anyone's definition of keyboard latency.
>Nobody measures keyboard latency this way (keypress travel)
You'll find most keyboards in your link, despite these fullrate-enabled high poll rates, actually have higher latency from keypress to event than what PS2 trivially achieved.
Which, by the way, is consistent with the findings in Danluu's article ("a joke"), showing that pressing 2 keys at once might not be as accurate, but does not completely compromise the results, relative to using a mechanical arm.
Note that Danluu documents his methodology, and even expresses that he would prefer a mechanical arm setup.
In practice, if you actually measure time from keypress to event, you'll find that modern "gaming" keyboards are actually laggy[0].
0. https://danluu.com/keyboard-latency/