The given key does not identify an element in this collection value for azure storage account primary_access_key output value

I am trying to pull the primary_access_key value from storage account foreach and assign to function app. However I am not able to get the primary_access_key value since it is not part of the foreach collection.

variables.tf

variable "stack_version"{
type = string
}
variable "functionappname"
{
type = string
}
variable "storage_list" {
    type = list
}
variable "rg" {
      type        = string
}
variable "loc" {
     type        = string
}

variables.tfvars

resourcegroupname = "test-rg"
location          = "eastus"
storage_list  = ["mystorageaccount"]
functionappname = "myfunctionapp"
stack_version   = { node = "~14" }

storage account module

resource "azurerm_storage_account" "storageaccount" {
  for_each = toset(var.storage_list) 
  name=each.value
  resource_group_name = var.rg
  location = var.loc
  account_tier = "Standard"
  account_replication_type = "GRS"
}

output.tf

output "sa_primary_access_key_out"{
    value = { for storageaccount in azurerm_storage_account.storageaccount : storageaccount.name =>  storageaccount.primary_access_key }
    sensitive = true   
}

output "sa_name_out"{
    value = { for storageaccount in azurerm_storage_account.storageaccount : storageaccount.name =>  storageaccount.name }
}

when I try to use storage account module output for Function app I am getting below error.

module "FUNAPP_StorageAccount" {
  source            = "../../modules/StorageAccount"
  storage_list      = var.storage_list
  resourcegroupname = module.ResourceGroup.rg_name_out
  location          = var.loc
}
module "FunctionApp" {
  depends_on = [
    module.ResourceGroup,
    module.StorageAccount
  ]
  source                            = "../../modules/FunctionApp"
  resourcegroupname                 = module.ResourceGroup.rg_name_out
  location                          = var.loc
  service_plan_id                   = data.azurerm_service_plan.shared-appservice-plan.id
  storageaccountname                = module.FUNAPP_StorageAccount.sa_name_out["mystorageaccount"]
  storage_account_access_key        = module.FUNAPP_StorageAccount.sa_primary_access_key_out["sa_primary_access_key_out"]
  functionappname                   = var.functionappname
  stack_version                     = var.stack_version                     
}

error:

│ Error: Invalid index
│ 
│   on main.tf line 45, in module "FunctionApp":
│   45:   storage_account_access_key        = module.FUNAPP_StorageAccount.sa_primary_access_key_out["primary_access_key"]
│     ├────────────────
│     │ module.FUNAPP_StorageAccount.sa_primary_access_key_out has a sensitive value
│ 
│ The given key does not identify an element in this collection value.

You do not have any key called sa_primary_access_key_out in your code defined. Instead you have output call that way. It should be:

storage_account_access_key        = module.FUNAPP_StorageAccount.sa_primary_access_key_out["mystorageaccount"]