The entire Kubernetes secret space is a bit immature with no standard solutions. Many of the larger solutions are vendor specific and don't solve the problem in a generic way, see AWS[1] or Vault[2][3].

I've been discussing the problem-space with the Godaddy External Secret maintainers and they seem a bit burnt-out. There is work on standardization here https://github.com/godaddy/kubernetes-external-secrets/pull/..., but this more covers creating Kubernetes Secrets from external sources, work still remains around a generic pod injector solution.

A few of us have started work on what the implementation of this would look like over at https://github.com/itscontained/secret-manager.

[1] https://github.com/mumoshu/aws-secret-operator

[2] https://github.com/hashicorp/vault-k8s

[3] https://banzaicloud.com/blog/inject-secrets-into-pods-vault-...