XPS 9570 not using Nvidia GPU

My XPS is rarely ever using the Nvidia GPU, even thoug it cant keep up with basic web browsing, video playback or just regular Windows. Everything stutters and is super slow, and I don't know what to do at this point. Everything is up to date, all the drivers etc. What helped was just to deactivate the Intel GPU in the device manager, expect that now the graphics seem somewhat weird and I cant control the display brightness anymore for some reason. At least Windwos and web browsing runs smooth now.

What do I have to do to force my XPS to always just use the dedicated GPU instead of the slow Intel?