8821cu-20210916 VS rtl8821CU

sudo apt update sudo apt install -y linux-headers-$(uname -r) build-essential bc dkms git libelf-dev rfkill iw mkdir ~/github cd ~/github git clone [https://github.com/morrownr/8821cu-20210916.git](https://github.com/morrownr/8821cu-20210916.git) cd ./8821cu-20210916 sudo ./install-driver.sh

The adapter you got should work fine, with the proper driver. I went to their driver download page, and got this archive for Linux Kernels: 4.19 - 5.11. Inside the archive, found the README.md file pointing to a github repository that contains newer versions of the driver https://github.com/morrownr/8821cu-20210916. You should give it a try.

if you want to make sure this is the correct driver for your adapter before going through the rest of the process, you can run the command lsusb. the id's will look something like 0BDA:B82B. the list of supported device id's is on this page: https://github.com/morrownr/8821cu-20210916/blob/main/supported-device-IDs

As I've said this one (rtl8821cu) is a pita to setup. Try this instead https://github.com/brektrou/rtl8821CU.

it looks like the driver is identified as the 8821cu. this looks like the more up to date driver listed on that page and is recommended in some of the probes listed below: https://github.com/brektrou/rtl8821CU

Install the dkms driver from here: https://github.com/brektrou/rtl8821CU (I'm 99% certain this is the correct driver).

That means, it can work with libre Debian systems without proprietary firmware in /lib/firmware. I installed this driver : https://github.com/brektrou/rtl8821CU. I was curious to where the proprietary firmware is, but I couldn't find a .bin file in the source code. Wonder if someone else more skilled than me can find it.

Then we are copying the code from the git repository (git clone https://github.com/brektrou/rtl8821CU.git), and move into the directory it created (cd rtl8821CU).