MacBook Pro M4 refresh rate limeted to 60hz since macOS 15.6 update

Hello,

My setup is a Macbook Pro M4, a FullHD Monitor via USB-C Dongle/HDMI on one port and one Display(Odyssey G70NC) with 4K 120Hz on another Thunderbold port. This worked fine.

Since I updated to 15.6 my Display won't dectect any refresh rate more than 60Hz. The 120Hz option is gone. I use a Displayport to USB-C Cable.

Has anyone a similar problem?