I was in OC 0.6.5 & Big Sur 11.2 - my WiFi was working (TL-WDN48000 - Atheros AR9380 chip).
When I updated to OC 0.6.6 & Big Sur 11.2.1 & WiFi did not work. OS can see the WiFi card, but cannot connect.
After a bit of research, somehow the sequence of AirPortAtheros40.kext & HS80211Family.kext is important! To make WiFi works, I needed to put HS80211Family in front of AirPortAtheros40.kext in config.plist.