According to the "Supported Hardware" list AX200 is supported: https://wiki.freebsd.org/WiFi/Iwlwifi#Supported_Hardware
Ah, even 802.11n is not supported! This is a 2009 standard. So we are left with 802.11a/b, which is 2003. The wifi of 21 years ago.
I'm curious - what do you do, or what use-case do you have in mind, that renders 16 Mbit/s throughput "completely unusable"? I never required 16 Mbit/s throughput for... anything related to my work. It's enough even for high-quality video conferencing.