Question about i-tec USB-C Universal Charger

Apparently (unfortunately) yes. This is the so-called "coil whine" or it is capacitors. In the case of a power supply unit, it is probably the coils. This effect often occurs at low or high loads due to a resonance of the electrically triggered vibrations with the material and can only be reduced/avoided by insulation or more expensive components. In addition, not everyone perceives these high frequencies. The function of the unit is usually not affected, so this is usually a "cosmetic" defect. There are actually only three options: a) hide the power supply under the desk / behind a piece of furniture so that the noise is muffled (make sure there is enough ventilation!) b) connect a switchable socket in between and disconnect the power supply from the power supply when it is not in use (my solution) c) complain, hope for goodwill and buy a more expensive power supply.