In post Turn on Hibernate in Windows 10, describe how to turn on Hibernate in Windows 10.
In Windows 11, even click on Change settings that are currently unavailable, Hibernate option is still missing.
Run following command in Administrator command line to show the Hibernate option
powercfg /h /type fullGoto Control Panel\Hardware and Sound\Power Options\System Settings
Click on Change settings that are currently unavailable, this is to enable check box of Hibernate
Check Hibernate
Click on Save Changes
Goto Control Panel\Hardware and Sound\Power Options\Edit Plan Settings
Click on Change plan settings beside current plan
Click on Change advanced power settings, then Power Options window appears
Expand Sleep->Hibernate after, change value in Settings
Goto Settings=>For developers=>Remote Desktop
Deselect Change settings so that the PC never hibernates when plugged in