Yes, this is possible with an open and closed notebook through the monitor's power delivery function. To do this, deactivate the USB-C power supply of the notebook in idle mode in the Admininstrator menu of the monitor.
Compatibility Mode ON = Power supply active in idle mode Compatiblitly Mode OFF = Power supply only when switched on
To start the notebook with the monitor switched on, please activate the function "Power On with AC attach" in its BIOS/UEFI.  Depending on the computer, the function name may be slightly different.