(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 
Looking for Big Sur support for AWUS036ACH . Currently there is just 10.14 MacOs drivers available.
@Rokland – that is not for Realtek chipset. Any updates about mediatek? https://files.alfa.com.tw/?dir=%5B1%5D%20WiFi%20USB%20adapter/AWUS036ACM/MAC%20OS/MacOS10.14
This update is not official, and you need to disable some MAC safety functions.
it’s sad to see people not even reading the article properly because it works very well
The link is in the first line of the article
Here is a workaround option for Big Sur. Please read the full article and understand that this driver workaround was not test by ALFA.
Bought mine last year and suddenly stopped around December 2020. I am currently running Big Sur on Mac and my other computer is running Ubunto 20 – both machine does not recognize the USB.
Please let us know when the driver is available soon.