Wifi dongle stopped working as soon a I upgraded to MacOS Big Sur 11 version
While Apple hasn't realeased an official date for when third party kexts, they have been phasing them out for over a year now and over time the list of depreciated kexts is growing.
For now I believe that you can boot into recovery mode using Command and R, and then running csrutil disable in the terminal.
This is more like a temporary hotfix than a solution and I would advise getting a new dongle if your manufacturer does not keep up.