Moved to SIEM for faster response. If this is wrong please advise.
When creating an alarm, you have a condition named "Device status change". You can select this, then check "Idle time".
Then in "Devices" tab, select all.
You can't however choose the timeframe after which it will trigger. You can only choose the alarm frequency (minimum time between two triggers).
You can also try using "system logger state change", also not editable, but did help us get a ahead of an issue recently.
Where do you find "system logger state change"?
In the Alarm I used an internal event match to signature ID 306-50014, and a separate one for device status change condition for SIEM devices. based upon the receivers and associated devices.
I backtracked these through some opsec events somewhere, I believe a health reference doc in knowledge base.