But how otherwise to convince people to always leave their surveillance devices phones switched on?! I had a oneplus 3t that would wake itself for alarms, shame it broke eventually.

You know what’s funny. I was investigating the hardware datasheets for the PinePhone and looking at the RTC module and just like PC RTC chips there is an option to trigger an interrupt/power on when a certain time is met. That means that there appears to be no reason this couldn’t be a current feature on probably all modern smartphones. Just lack of software support.