It is unfortunate that OP has this sort of issues. i had none of it and with the same card ( are there any revisions of it i wonder ? ) and iwx driver. To give more information about my setup - i have only 2 changes: blocklist of if_iwlwifi and if_iwm. i preload firmware for ax 210 in /boot/loader.conf. while this is not supported as said by iwx driver developer this working really well and should supported in my opinion.
