I am working connected remotely via ssh to this NUC and sometimes it just hangs and stops accepting commands from the keyboard for severa seconds. This NUC is running Linux. Here in the video I demonstrate how the ping command just hangs instead of pinging every second:
The problem happens also when connected directly to the NUC with a keyboard and mouse.
I don't know if this is a Linux problem or a hardware problem. I have not tried using Windows but it happened in all Linux distributions which I tried. This is my first NUC and it's 2 days old. I know the CPU in this one is not very powerful (Pentium Silver) but this should not happen. There is no load on this server, it's a fresh installation.
But to add to the discussion in case someone hits the same problem, the situation is improved by disabling the power savings in the Linux kernel:
sudo iwconfig wlp0s20f3 power off
Not completely, so upgrading is still on the list, but it's usable, at least there aren't anymore so many interruptions.
Reporting back. I simply replaced the Wireless-AC 9462 with the Wi-Fi 6 AX201 and it worked right out of the box.
I don't know what was wrong with the original 9462 card, maybe it was defective, the AX201 is flawless.