You may want to consider a tool like Hashicorp's Terraform. That will allow you to define infrastructure like you Kubernetes cluster and other resources that you'll require in much the same way that you define them with ARM Templates. It actually will allow you to directly use ARM templates, so you should be able to reuse most of what you've done without rewriting it all into Terraform. You'll also be able to load Helm charts and even do things like provision DB users and so on.

Helm is a tool that helps you build templates (“charts”) of your application.
They are like ARM templates for your application definition. I don't think currently we have the option to deploy applications with Helm using Azure Resource manager templates.

I would recommend reading through these documents for ways to deploy application to AKS with Helm: https://docs.microsoft.com/en-us/azure/aks/kubernetes-helm https://microsoft.github.io/PartsUnlimitedMRPmicro/hols/deploy-acs-kubernetes-helm.html