I've deployed Harbor on my K8S cluster as follows:

helm install dockistry harbor/harbor \
  --set expose.type=ingress

Then the ingress ressource shows:

kubectl get ingress
NAME                       HOSTS                                     ADDRESS          PORTS     AGE
dockistry-harbor-ingress   core.harbor.domain,notary.harbor.domain   xxx.xxx.100.61   80, 443   2m43s

The HOSTS is wrong and would like to change it. How can I edit dockistry-harbor-ingress ?

kubectl edit ingress dockistry-harbor-ingress

will open up an editor where you can edit and then save it which automatically applies the change to the cluster.

Alternatively you can kubectl get ingress dockistry-harbor-ingress --export -o yaml > ingress.yaml to save in a yaml and edit it and then apply it via kubectl apply -f ingress.yaml