How is video-nvidia compared to video-hybrid-intel-nvidia-prime perfomance-wise?

Should I expect better framerates when playing games on the video-nvidia driver compared to the hybrid one?

It normally should, unless your device is organized such that it can’t bypass Optimus (read: turning the Intel card totally off) anyhow. For these devices, usually one must run the device connecting the external display as it’s the one that’s normally connected directly to the dGPU.

errr … maybe, probably.
But you will waste power otherwise, and also suffer the effects of dealing with proprietary nvidia on an open linux desktop.
In most cases, unless you really dont care (in which case you should disable the intel entirely - at bios if possible) you should use the hybrid setup for your hybrid system.