this is NOT a limitation of Android. Android has supported wakelock based notification managers for a long time. And FCM works pretty much the same as was menti

this is NOT a limitation of Android. Android has supported wakelock based notification managers for a long time. And FCM works pretty much the same as was mentioned in the OP. The FCM manager maintains one long polled connection to Google notification servers and every other app subscribes to wakelocks from that manager. Your app is only woken up by the OS if FCM receives a notification for you. For e.g. Xiaomi will not wake you up even if you get a notification, unless you're on a white list (the much glorified Xiaomi whitelist). When Android is put in power saving mode, the FCM manager optimized this even further.