Kubernetes Cluster using Kops in AWS

I have a question, I am try to bump a cluster(inherited) which is in just one AZ us-east-1a in each environment Sandbox, qa, PROD. The ask is to have HA and deploy it also in another AZ, say us-east-1b. Now in us-east-1a, we have 3 master nodes, and we have 6 worker nodes.

My question is do i deploy a full cluster(same 3 master nodes and 6 worker nodes) in us-east-1b, but how do ensure HA when one AZ is down. Also there are talks of using Federation KubeFed v2 for the clusters, but thats deprecated and doesnt have much support. We are trying to start our kubernetes architecture and design from scratch using EKS, so we want minimum effort and simplest solution for the present kubernetes setup we have till we move to using EKS with a proper design, any Takers?