Using Apple wireless KB which seems to work except in waking up; it may work if the "sleeping" has been for a short period but this is conjecture as I've noticed the KB does seem to function if I have initiated "sleep" via the menu and then used a key stroke shortly after. "Diagnostics" also doesn't seem to function on this (MontereyOS) device which may be related.
In case others find this thread looking for a solution: "sleep" according to the MacOS user guide doesn't happen unless selected or scheduled; nonetheless it appears or is implied -from the Energy saver area that one can schedule the screen to turn off after a selected time and it seems to "sleep" a while after (or maybe this is yet another secret/unstated feature with some other name; anyway I tried three things and it now awakens after about a second using any keyboard key. The three things were: Turned off device for an hour or so/ re-set the NVRAM/ asked for advice on a Facebook group. One or more of these seemed to work; probably not the latter but it was after I got some useless reply that I tried the keyboard again.
Avoid manual sleep and disable auto Sleep. It’s unnecessary on later Macs, all pain, no gain. Shut for long absences i.e. > 2 hours. To disable, check “Prevent…” in Energy Preferences and uncheck everything else. You can leave the display off time as is, unrelated to Sleep.
Keyboard (KB) usually won't wake up iMac; makes popping sound; in Bluetooth; no keyboard found.
