Issue in creating DNS record for azure dnszones in terraform

Objective: Trying to create DNZ Zones and DNS records via terraform on Azure

Code that I tried:

My Variable.tf:

variable "subnets" {
  description = "subnet address prefixes to respective environments"
  type = any
  default = {
    dev = {
        gw_snet = {
            attach_nsg = false
            virtual_network_name = "vnet-hub"
            name = "GatewaySubnet"
            address_prefixes = ["xx.xxx.x.x/xx"]
        }
        dns-snet = {
            attach_nsg = false
            virtual_network_name = "vnet-hub"
            name = "DNSSubnet"
            address_prefixes = ["xx.xxx.x.x/xx"]
        }
        common_snet = {
            attach_nsg = false
            virtual_network_name = "vnet-hub"
            name = "CommonSubnet"
            address_prefixes = ["xx.xxx.x.x/xx"]
        }
        clientdata_snet = {
            attach_nsg = true
            virtual_network_name = "vnet-hub"
            name = "ClientDataSubnet"
            address_prefixes = ["xx.xxx.x.x/xx"]
        }
    }
    }
}

My main.tf:

resource "azurerm_private_dns_a_record" "monitor_snapshot" {
  for_each = { for k, v in var.subnets[var.env] : k => v }
  name                = "snapshot"
  zone_name           = azurerm_private_dns_zone.monitor.name
  resource_group_name = azurerm_resource_group.rg[0].name
  ttl                 = 3600
  records             = [cidrhost(azurerm_subnet.mysubnet["gw_snet"].address_prefixes[0], 11)]
}

Issue that I am facing:

Since I used creating multiple subnets using for_each in loop, so when I try to create dns record using particular subnet , here in this case "gw_snet" but, terraform is erroring out as it tried to add dnsrecord for each subnet which I dont want.. only using gw_snet it has to create.

can you please suggest what mistake I am doing here ?