When you install k3s it automatically come with Traefik installed.
Traefik is great but if you need to work with an other ingress, you might want to remove it.
Here is how:
# Remove traefik helm chart resource
sudo kubectl -n kube-system delete helmcharts.helm.cattle.io traefik
# Stop the k3s service
sudo service k3s stop
# add option to add to ExecStart "--no-deploy traefik \"
sudo echo '--no-deploy traefik \' >> /etc/systemd/system/k3s.service
# Reload the service file
sudo systemctl daemon-reload
#Remove the manifest file from auto-deploy folder
sudo rm /var/lib/rancher/k3s/server/manifests/traefik.yaml
#Start the k3s service
sudo service k3s start