Terraform: Use count.index in variable name

Is it possible to use count.index in a variable name, so I can use a single map variable for multiple resources? For example

variables.tf:

variable "disk_share_sizes" {
  type        = map(number)
  description = "Sizes for VM Disks and File Shares"
  default = {
    fileshare   = 2048
    pvs0        = 20
    pvs1        = 10
    cca0        = 50
    cca1        = 80
  }
}

compute.tf

resource "azurerm_managed_disk" "vm_pvs" {
  count                = 2
  name                 = "pvs-disk-${format("%02d", count.index + 1)}"
  location             = "useast"
  resource_group_name  = "MyRGName"
  storage_account_type = "MyStorAccount"
  create_option        = "Empty"
  disk_size_gb         = var.vm_disk_sizes.pvs[count.index]
}

resource "azurerm_managed_disk" "vm_cca" {
  count                = 2
  name                 = "cca-disk-${format("%02d", count.index + 1)}"
  location             = "useast"
  resource_group_name  = "MyRGName"
  storage_account_type = "MyStorAccount"
  create_option        = "Empty"
  disk_size_gb         = var.vm_disk_sizes.cca[count.index]
}

This produces the below error (repeated for both resources):

│ Error: Invalid index
│
│   on compute.tf line 8, in resource "azurerm_managed_disk" "my_vms":
│  8:   disk_size_gb         = var.vm_disk_sizes.vm[count.index]
│     ├────────────────
│     │ count.index is a number
│     │ var.vm_disk_sizes.vm is a number
│
│ This value does not have any indices.

I can't use "var.vm_disk_sizes.vm${count.index}" as this is a variable name and putting it in double quotes will just make it a string. I did try using ${var.vm_disk_sizes.vm${count.index}} but it doesn't like this either

Can this be done without making the variable a list rather than a map? I'm using a map as my actual map is larger, and it would be difficult to split this into multiple lists for all the different VMs and disk sizes.

Ideally, you would use the for_each meta-argument instead (since your variable is defined as a map):

resource "azurerm_managed_disk" "my_vms" {
  for_each             = var.vm_disk_sizes
  name                 = "vm-disk-${each.key}"
  location             = "useast"
  resource_group_name  = "MyRGName"
  storage_account_type = "MyStorAccount"
  create_option        = "Empty"
  disk_size_gb         = each.value
}