On iPhone, you can use the Shortcuts app to do this. Create a new shortcut with the Restart action and save it. Then go to the Automations tab, set the schedule, and select your new shortcut. Make sure it's set to Run immediately.
Out of curiosity (and because I'm not going to try that for tomorrow morning) – does that kill my alarms, or does iOS schedule/store these somewhere accessible before first unlock?
I travel a lot so have it turn on specific data SIMs when GPS detects I’m in that country.