New Mac Mini (Sept. 2022) won't sleep through the night; requires log-in every morning. AppleStore guru checked all settings, found nothing to alter. Mini draws power from a battery backup; therefore power fluctuations aren't the problem. Updating to Monterey 12.6 didn't help.
Mac mini, macOS 12.6
You’re not the only one with a sleep issue.
Check “Prevent your Mac from automatically sleeping….” and manually test sleep from the Apple dropdown menu. Or… optionally leaving the Mac mini on with the display(s) off or shut it down at the end of each day.
In addition you can send detailed feedback to Apple about this issue.
Mac Mini
