Auto logging off issue on iMac
iMac 27″, macOS 15.7
Question marked as
The setting that you are looking for is at Apple > System Settings > Lock Screen > Require password after screensaver begins or display is off.
If you can not adjust that setting, then the iPhone Mirroring App maybe preventing you from changing it.
To fix that, open the iPhone Mirroring App on your Mac and change the setting to "Ask every time"
Then you should be able to adjust that setting to longer Time or to Never.