GNU/Linux Debian Bullseye ALFA Network AWUS036ACS Wifi Adapter Driver Setup – Step-by-step Guide
Hi! The linked Tutorial shows you Step-by-Step How to Install Alfa Network AWUS036ACS Wireless AC750 USB Dongle Driver in Debian Bullseye 11.x GNU/Linux.
And the Debian 11 ALFA Network AWUS036ACS Setup is based on the Realtek rtl8811AU Chipset Driver Installation.
But the Realtek rtl8812AU/rtl8821AU Driver following the Realtek Documentation is supporting also the rtl8811AU Chipset.
So you may try first with the rtl8821AU Driver Setup and eventually switch to the rtl8812AU.
GNU/Linux Debian Bullseye Installing Alfa Network AWUS036ACS Wireless Driver