Very interesting, where do you see value:
a.) in Kubernetes setups that operate the same software stack, with the ongoing updates and regular releases.
b.) in Kubernetes setups that frequently install new software/diverse software
A package manager for a software stack the does not change that often (a) can move managed services like databases, message queues or even more complex obseravbility tools inside the cluster with the same convenience of a manage service.
If your setup become more complex and changes often (b) a I would recommend breaking it up into smaller pieces.
For both scenarios it makes sense to use git to keep track of revision and previous states of your Kubernetes cluster and incorporate review processes with pull requests.