Can you provide more context? I unfortunately don't understand what you're asking for.

Status:
At the moment a worker node of a AWS EKS cluster runs with the volume_type 'gp2'

Terraform aws_instance resources provides options to configure a root_block_device:
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance#ebs-ephemeral-and-root-block-devices

Goal:
As a Kubestack end-user I would like to have the option to configure the worker node root_block_device with the following options:

• volume_type
• iops

The nodes are created using the aws_eks_node_group ressource. I believe the corresponding attribute for the launch_template used for the aws_eks_node_group would be this: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/launch_template#block-devices

However, that's not currently exposed yet by Kubestack's EKS node_pool module.