Using basic K8S resource files requires a lot of duplication, when using Kustomize or Helm isn't supposed to be that difficult to create an abstraction so that you can adopt you templates for multiple environments/purposes and inputs. With library charts in Helm 3, this should help even more to create a list of standard services or dependencies within your template files that can be quickly adopted throughout the organization. Once you have a few templates, then they can be quickly adopted.