first disable systemd-resolved service.
systemctl disable systemd-resolved.service
Stop the service
systemctl stop systemd-resolved.service
Then, remove the link to /run/systemd/resolve/stub-resolv.conf in /etc/resolv.conf
rm /etc/resolv.conf
Add a manually created resolv.conf in /etc/
nano /etc/resolv.conf
Add your prefered DNS server there
nameserver 8.8.8.8