> Plus of course, even if you do polling, if you have 5 different apps that connect every 10 minutes to their own respective services with different offsets, you have the device waking up every 2 minutes,

This is now impossible with background execution restraints set in Oreo. The OS clusters requests for background execution and does them with the same wake. Apps can only wake the device every 15 minutes at most (and requests to wake are not guaranteed).