Paramedics will check the obvious places (neck, wrists and ankles) for MedicAlert style ID but it's not their job to identify you or notify your next of kin. That'll be done by the police and/or the hospital staff. They'll be the ones who might look at a phone or in a wallet, etc.
Believe you me, they won't. They'll assess your injuries, look for obvious MedicAlerts (wrist, neck or ankle), stabilise and then convey. They won't be wasting time looking for QR codes or scanning them (assuming they even have a work issued* QR-enabled phone, in an area with a signal).
*if they didn't have a work issued QR-enabled phone they shouldn't be using their own, as that would raise all sorts of IG issues.