Same problem here, iwlwifi with AX200. Looking at the module options, I noticed that the the debug interface is enabled by default. Long shot, so I added options iwlwifi enable_ini=0 to /etc/modprobe.d/99-local.conf and rebooted. Lo-and-behold, system boots as usual and iwlwifi seems to work in kernel 5.10.1 as well. Let's see what upstream comes with, but so far it looks like there is a workaround.