I don't understand you.

For very simple deployments, you don't need anything at all. Just write manifests and use `kubectl apply`. You can write `deploy.sh` but it'll be trivial.

If you want templating, there are many options. You can use `sed` for the most simple templating needs. You can use `cpp`, `m4`, `helm` or `kustomize`. I, personally, like `kustomize`, but `helm` probably not the worst template engine out there.

Kustomize is even somewhat included into basic kubernetes tooling, so if you want something "opinionated", it is there for you. It works.