I presume this to be something that would require development in AOSP - but my iPhone could receive "Critical Notifications" from Home Assistant. These would always give a loud audible chime on the phone regardless of do not disturb / silent / etc and a clear pop up notification that required dismissing.
I can configure a notification channel in HA that can then have specific settings on the phone in Graphene, but I don't seem to be able to set this to be a loud audible notification regardless of the the state of the phone.
Is this possible?