I had the weirdest thing happen earlier.
Was testing my old Lenovo craptop, its extremely weak, barely above Atom and wanted to fact-check that Lenovo do not whitelist all their laptops and so confirm an AX200 WiFi card works in it. Weird thing, it got down 840Mbit down and 1.2Gbit up on iperf3 with a 2400Mbit link rate.
My faster machines including Macbook Pro M1 and an AX210 WiFi in my gaming laptop never gets those speeds, their link rate is usually 1200Mbit or 1600Mbit at best. So this really took me by surprise and now I'm left wondering why the better machines can't at least hit Gigabit. The Macbook tested straight after in the same place was getting 650Mbit.
Of course I can't dismiss its an iperf3 glitch as I've seen it give dubious results before, but then the link rate makes it plausible.
Makes me think I should test my other AX200 card, if I can remember where it is. Would be really weird if the AX200 performs better on WiFi 6 than the AX210, given the AX210 performs better on WiFi 5 than the AX200.