The only thing helm provides is awkward templating, IME. Ideally you'd never use a text template library to manipulate YAML or JSON structured objects. Instead you'd have scripts that generate and commit whole YAML files, or you'd just update the YAML manually (less optimal), and then you'd write those to the k8s API directly or through a purpose-built tool.

(Or, hell, helm but with no templating whatsoever).