Flutter - Modify my in-app pop up notification (existing) to Full screen Ring

To create a full screen notification that's able to wake the phone from sleep. We already have the normal pop up notification but it's not good enough. We prefer the kind of notification that will constantly ring until it's turned off, just like the whatsapp call or the alarm ring.

We have a full backend team running in Php Laravel, and our front end flutter app is already fully functional.