I constantly have to wrestle with Sleep Mode. Even though my Power Setting are correctly set there's always something else, a software, a hardware, a drivers, etc, that disturb those settings and prevent them from functioning correctly. One day everything works and the next day my PC doesn't go...
bios uefi
driver conflicts
drivers
energy saver
event viewer
fast startup
hibernate vs sleep
lid switch
power policy
power settings
powercfg
sleepexceptionssleep mode
system power management
task scheduler
unexpected wake
usb selective suspend
wake on lan
wake timers