(EDIT March 24, 2021, we have a NEW UPDATE about Big Sur. Click Here to read this information that is newer than what is posted below).
If you already own an ALFA 802.11ac USB WiFi booster and have followed our steps to get it to work on Mac OS 10.15 Catalina, you may be wondering if you upgrade to Big Sur (released by Apple today, November 12th), if your product will still work after the update. Operating system upgrades can often times break hardware.
The good news is we have tested it today and can confirm with the 11.0.1 release the ALFA AWUS036AC and AWUS036ACH still work well.
We have not yet confirmed if you can do a new install the same way you can on Catalina. So if you do not yet own an ALFA AWUS036ACH and are looking to get one and install it on Big Sur, we have not yet confirmed the installer will work. We should have an update on that in the next few days and will post to our blog.
Military and First Responder 
Hi Jurgen,
Unfortunately this is outside of our control. We will announce as soon as the Big Sur driver is available.
So, March 8, and still no update. You guys told me earlier that by now there should be a driver available for OSX Big Sur?…
AWUS036ACH doesn’t work with BigSur, we are waiting for the updated driver…
Is there a driver anywhere for the AWUS036AC for big sur anywhere. Shouldnt be that difficult.
yeah…. this sucks. please fix this guys. just adding another comment to the list so they can see how many people are not happy about this…..anyone that may have a fix please let us know!