I believe BuildKit solves the dependency graph problem. Docker has shipped with it since 18.09. It is opt-in for now so you have to use e.g. `DOCKER_BUILDKIT=1 docker build ...`.
https://docs.earthly.dev/examples/monorepo
At least it addresses building the right Docker image--it doesn't seem to address building the broader Kubernetes manifests, but I'll take what I can get at this point.