Is Workloads share across all nodes in kubernetes cluster

i have 3 worker nodes in Kubenetes cluster (AKS or EKS), each node have 2 cpu and 2gb RAM

My Application maximum requirement is 2CPU and2 gb RAM

i have deployed applicaton in pod with replicaset, so now my application is running in all 3 nodes.

What my question is

My application load has reached high in node 1 means, what happens

Is that load has been shared across the nodes in cluster or i need to add another node for performance.

I want to conclude that my application in all three node, IS that workload and network has been shared by cluster? i meen one node have 2cpu and 2gb ram, now based cluster architecture now i have 2cpu and 2gb ram * 3 6cpu and 6 gb RAM right is my understanding right

i know all the nodes or Highavailability.