What GPU?
Some models have issues with the latest drivers when comes to Display Port or some like that
You could probably try to make use of the video-nvidia-470xx drivers instead.
Also, instead of enabling that monitor from Nvidia Settings, do it from the System Settings. As it seems you are on KDE Plasma … do that first, then try to open Nvidia Settings. Also, if you want to make a fixed layout, don’t forget: the correct file to alter is /etc/X11/mhwd.d/nvidia.conf