> Cleanups: I want to do a `helm uninstall` and have all the manifests go away at once instead of looking around for N different resources.

    kubectl delete -f <manifests.yaml>

    kubectl delete -k <kustomization_directory>

> I want to apply my database migrations and populate the database with static datasets before I deploy my application, without having my CI connect to the database cluster

A Job feels like a good fit for this. CI deployes the Job without connecting to DB, Job runs migrations using the same connectivity as the application.