How do I install drivers for UGREEN USB WiFi Adapter AC650?
From journalctl results you've posted, your USB wireless adapter, idVendor=0bda, idProduct=c811, needs rtl8821CU drivers.
You can install the drivers from this GitHub repo:
sudo apt update
sudo apt install build-essential git dkms
git clone https://github.com/brektrou/rtl8821CU.git
cd rtl8821CU
chmod +x dkms-install.sh
sudo ./dkms-install.sh
Ref: https://askubuntu.com/a/1264759/928088