My previous work used a system which queued notifications for delivery. The logic was something along those lines:
- send notifications for urgent items, e.g. incoming calls, immediately to all devices - if there are no active devices, send all notifications immediately - otherwise send to all active devices st internally along with testers.
I ended up tweaking this; it took us a few tries to get it right. I'd be flabbergasted if Facebook messenger, iChat, discord et al haven't done something similar.
1. https://github.com/vector-im/element-android/issues/4147 and also some other
Often when my phone is left behind somewhere in the apartment, my SO will ask me to do something with those notifications, or just will move my phone away from her (and/or my tablet).
BTW it seems that other communication devices did it right. I just tested Google Chat, and I remember that I did not have this issue neither with Slack.