The cable with DisplayPort connector to HDMI (type A) is designed to transmit a signal from a DisplayPort source to an HDMI input. In your case, you want to connect the screen (without HDMI output, but with DisplayPort) to the Nintendo Switch (which only has HDMI output).

This does not work as the cable only transmits signals from DisplayPort (source) to HDMI (receiver), not the other way round. The switch sends out an HDMI signal that a DisplayPort input on the monitor cannot process directly. An active HDMI to DisplayPort converter would be required to connect the HDMI output (switch) to the DisplayPort input (screen), not a simple cable.

In short: The cable is not suitable for connecting the switch to a monitor with DisplayPort input only.