2 alarms, one on the iPad, one on the phone. Full volume, spaced 10 minutes apart.
Edit: these go off almost 2 hours before I have to leave, and I’m asleep 7-8 hours before they go off. My biggest difficulty in waking up on time is not going to bed with enough time to fall asleep for 8 hours.
I have a hard-stop alarm, set 9 hours before I have to wake up, to remind myself to get ready for bed. A full sleep cycle (including morning routine) is an 11-hour time investment for me.