You have meta packages installed.
You chose to install linux56-rt-headers (or linux-rt-manjaro) and linux-rt-manjaro-headers
They rely on eachother … so you need to remove them both.
Also … is there any reason you want to RealTime kernels? Those are really just for recording studios and such.
Thats great. But everything above only has to do with package dependencies, not the drivers themselves… so it doesnt really have much to do with nvidia.