Question about Aten Cs1794

I use this without problems with a UHD 2160p monitor. That is, a 4K screen.
I am very satisfied with the product, but I do not use all the features, especially in the audio area, for the connection with a headset on the CS1794, I had problems to achieve the desired result. However, it was not that important to me and I certainly did not try out everything. Audio playback with the screen works without any problems.

No. According to the manual, only 1080p (HDTV) or 1920 x 1200 (DVI) is supported.