Message TTL issue at Firebase Admin SDK

Question

I'm trying to add TTL to push notification payload so messages are either delivered in the next 16 hours (57600 seconds) or discarded by FCM. While messages themselves being sent/delivered with payload attached below only Android TTL value is honoured by FCM on fan out. I set up data transfer to Big Query for Firebase Messaging and it shows that TTL is standard 28 days (2419200 seconds) for non-Android platforms.

The question is: what am I possibly missing, and how to properly pass TTL for Webpush and APNS payload to be honoured by FCM?

A little overview of environment setup - there's PHP server which prepares push notification payload and sends it to Firebase Cloud Function, cloud function then retrieves payload and calls admin.messaging().send() with it as a param.

I used these docs to pass values for Web and iOS: https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.webpushconfig https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.apnsconfig

And here's an example payload I'm passing to admin.messaging().send():

{
  "webpush": {
    "headers": {
      "TTL": "57600",
      "Urgency": "normal"
    },
    "notification": {
      "title": "Test Tokens Send",
      "body": "Test",
      "tag": "test-recommended-reads",
      "icon": "/wp-content/uploads/.../icon-512.png"
    },
    "data": {
      "title": "Test Tokens Send",
      "body": "Test",
      "tag": "test-recommended-reads",
      "clickType": "openPost",
      "clickValue": "{\"postId\":999999,\"postUrl\":\"https:\\/\\/some.site\\/post-name?utm_source=SITE&utm_medium=Notification&utm_campaign=test-recommended-reads\"}"
    }
  },
  "apns": {
    "headers": {
      "apns-expiration": "1707780517"
    },
    "payload": {
      "aps": {
        "alert": {
          "title": "Test Tokens Send",
          "body": "Test"
        },
        "mutableContent": true
      },
      "clickType": "openPost",
      "clickValue": "{\"postId\":999999,\"postUrl\":\"https:\\/\\/some.site\\/post-name?utm_source=SITE&utm_medium=Notification&utm_campaign=test-recommended-reads\"}"
    }
  },
  "android": {
    "ttl": 57600000,
    "priority": "normal",
    "data": {
      "title": "Test Tokens Send",
      "body": "Test",
      "tag": "test-recommended-reads",
      "clickType": "openPost",
      "clickValue": "{\"postId\":999999,\"postUrl\":\"https:\\/\\/some.site\\/post-name?utm_source=SITE&utm_medium=Notification&utm_campaign=test-recommended-reads\"}"
    }
  },
  "fcm_options": {
    "analytics_label": "test-recommended-reads_24-02-12_07:28"
  },
  "topic": "test-recommended-reads"
}