I could not find any post on timelines for an debian 12. https://learn.microsoft.com/en-us/azure/iot-hub-device-update/support?source=recommendations#linux-operating-systems
You can request this on the feedback portal as engineers constantly check to see possibilities:
https://feedbackportal.microsoft.com/feedback/
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola