So according to Energystar.gov, the annual energy consumption is 65.97 kWh/year. This calculation is based on the monitor being 35% in On mode and 65% in Sleep mode over a full year.
https://www.energystar.gov/productfin...

Nevertheless, the above value of 40 kWh/year (from the series of pictures) may still be correct under certain circumstances, as our Federal Office of Energy calculates/calculated as follows for the above original label: 4h/day operation over 365 days. Now the dilemma: There was/will be a revision from 1 March 2021 for the energy efficiency class table. It will now be given per kWh/1000h instead of over kWh/year. This can lead to a device with A+++ (on the old list) dropping down to C (on the new list) - 5 steps down. For this monitor, class A (old list) corresponds approximately to class F (new list) - 5 steps down.
https://www.bfe.admin.ch/bfe...

This device was released on 28 October 2020 via EU DECLARATION OF CONFORMITY. Therefore, the energy efficiency class above (and everywhere else) is still class A - except for the new labels that come with the product. These are already up-to-date and are therefore classified as class F.
https://downloads.dell.com/rdoc...

A label with energy class F is attached to the screen.

https://newlabel.ch/