Best way to alert on missing IoT Wireless frames

I'm trying to diagnose when Wireless Gateway's fail to receive LoRa frames. I'm looking specifically at the FCnt of device uplinks and noticing some missing numbers. I understand this could be for a variety of reasons, but I'd like to set up some kind of metrics/alerts for when and how often it happens.

I had thought of tracking FCnt by device in DynamoDB, but it would be even nicer if there was a way to do so on the Device object itself inside IoT without managing a separate service.

Could use some recommendations...

{
  "WirelessDeviceId": "<<redacted>>",
  "PayloadData": "<<redacted>>",
  "WirelessMetadata": {
    "LoRaWAN": {
      "ADR": "false",
      "Bandwidth": 125,
      "ClassB": "false",
      "CodeRate": "4/5",
      "DataRate": "3",
      "DevAddr": "<<redacted>>",
      "DevEui": "<<redacted>>",
      "FCnt": 8953,
      "FOptLen": 0,
      "FPort": 2,
      "Frequency": "904900000",
      "Gateways": [
        {
          "GatewayEui": "<<redacted>>",
          "Rssi": -47,
          "Snr": 13.25
        }
      ],
      "MIC": "f4f98a6b",
      "MType": "UnconfirmedDataUp",
      "Major": "LoRaWANR1",
      "Modulation": "LORA",
      "PolarizationInversion": "false",
      "SpreadingFactor": 7,
      "Timestamp": "2022-07-07T02:06:53Z"
    }
  }