Hi Walti,
I assume it is this camera https://www.amazon.co.uk/dp/B07DJCZQ74/ref=psdc_1330828031_t1_B07DJC8YX2 in English version 
I have no experience of this camera so search on Internet what other users know.
From the Customer Q&A I read that the camera support the ONVIF standard and also use the protocol rtsp for streaming of video and audio.
NCS support the ONVIF standard. When you add a camera to NCS use the tab for ONVIF Source. If that do not work it seems that ieGeek cameras use the URL rtsp://cameraIP:554/11 So in the tab for Custom URL set stream type to rtsp_tcp and use the URL rtsp://username:password@cameraIP:554/11
If all the information about the camera is correct this will work.
Notice also that a 1080p camera use more computer resources than 720p. FPS from the camera, recording FPS etc will also effect the cpu load.
Good luck!
Henrik