Create Terraform Cloudwatch Dashboards dynamically

Question

Overview

Currently, dashboards are being deployed via Terraform using values from a dictionary in locals.tf:

resource "aws_cloudwatch_dashboard" "my_alb" {
  for_each       = local.env_mapping[var.env]
  dashboard_name = "${each.key}_alb_web_operational"
  dashboard_body = templatefile("templates/alb_ops.tpl", {
    environment = each.value.env,
    account     = each.value.account,
    region      = each.value.region,
    alb         = each.value.alb
    tg          = each.value.alb_tg
  }

This leads to fragility because the values of AWS infrastructure resources like the ALB and ALB target group are hard coded. Sometimes when applying updates AWS resources are destroyed and recreated.

Question

What's the best approach to get these values dynamically? For example, this could be achieved by writing a Python/Boto3 Lambda, which looks up these values and then passes them to Terraform as env variables. Are there any other recommended ways to achieve the same?