Resolution Problem after DDPM 2.2.0.19 Installation

Hey,

So i have got a new Dell P2425D, Resolution 2560x1440@100hz. Setup: 2x HP G5 Dock; Monitors: 1x Acer 1920x1080@60Hz Monitor, 1x Lenovo 2560x1440@100Hz Monitor, 1x Dell P2425D 2560x1440@100Hz ; Laptops: Dell Precision 7860, Lenovo Thinkpad x280, Lenovo Legion 5P. 

Soo, i plugged everything in. Worked like a charm. Then i installed DDPM 2.2.0.19 on the Thinkpad x280. Now it only gets 1920x1080@60Hz on two monitors, not more.
On the other 2 Laptops it still work fine with any combination (up to 2x 2560x1440@100Hz), so it has to be a software problem. The DDPM something up massivly. How do i return the Thinkpad x280 to the previous state?

I Already reinstalled graphic and usb / thunderbolt drivers, deinstall of ddpm and all dell tools.
Support just told me the usual reinstall graphics driver, did that. Closed the case then. Won't be getting more help there. Is just sad, got this P2425D yesterday. Support was really friendly but could not help much.

Can anyone tell me the Dell Display and Peripherie Manager so baldy, that it permanently reduces the bitrates of Thunderbolt? Or disables MST or something?
Please help, i am at wits end.
best regards