I found some topics similar to this, but the solutions appeared to be specific to XFCE? And I did not find an equivalent in Deepin.
Control Center – Power – Battery and for Plugged In I have it set for Suspend on lid closure.
Closing the lid though does not put the computer to sleep/suspend.
Control Center – Power – Battery and for Plugged in I also have it set to suspend when power button is pushed. This one does work.
So maybe somehow it is simply not registering a lid closure?
Let me know if I need/should provide more information.