Dell Monitor U4919DW DDM for macOS 11.6.1

I've purchased an U4919DW monitor 2 months ago and was happy to find out that finally a macOS firmware is available for the monitor: M2B907

I've installed the firmware on the monitor and downloaded the latest DDM version: DDMv1.50.0.0042

But after installing the DDM version, I'm still getting an error when I'm trying to open the DDM manager:

I've had a 30 minutes talk to the Dell support but without any success. They've told me that it should work fine, and my computer is the issue. He ended the call. If the DDM don't work, I'll send my monitor back and buy something else. Such a big monitor needs a good window management!

PS: They have also sent a link to this page and told me to follow the instructions. The funny thing is, that they are only for Windows: https://www.dell.com/support/kbdoc/de-de/000060112/was-ist-dell-display-manager