//Solution:
I installed this driver (https://github.com/morrownr/8821au-20210708).
The driver however, did not work until I ran a script called remove-driver.sh from the driver that I used to use (https://github.com/morrownr/8821cu-20210916). Then the wifi adapter started working again :)
Thanks a lot for the help - I am still not really sure what the problem actually was, but I'm very thankful for having my internet connection back :)
//Original post below:
Hey :)
I've been using a wifi adapter for my computer for about a year. A few days ago, it suddenly stopped working. It no longer shows up when I run 'nmcli device' in the terminal. When running 'lsusb' it still shows up as 'Realtek Semiconductor Corp. 802.11ac NIC'.
To my knowledge I hadn't updated anything before it stopped working. After it had stopped working, I used usb-tethering from my phone to do a system update, hoping it would fix the problem. I think one of the updates was a linux firmware update. Anyways, it didn't fix anything.
The adapter didn't work out of the box. It arrived with a driver called 'RTL88x2BU' and a document stating that it was compatible with the following chip drivers for linux: RTL8811AU RTL8811CU RTL8812BU RTL8814AU
I couldn't get the driver it arrived with to work, so instead I downloaded this driver and have been using it until it stopped working. https://github.com/morrownr/8821cu-20210916
this driver only states that it supports some linux kernel version. I'm using '6.8.0-40-generic', which it does not claim to suppport. I download this driver, which should support my kernel, but it didn̈́'t work either. https://github.com/morrownr/8821au-20210708
I've tried running lsmod on my system, and it seems to be, that no wifi driver even starts. The only thing I can remember doing just prior to my internet not working, was running 'systemctl disable jellyfin.service'. I doubt that has anything to do with this, but I'm not sure what else it could be. My only other theory is, maybe the usb wifi adapter hardware just gave up.
Any help is appreciated ^^