Hi,
It shouldn't be a problem to do so.
I would update all your HikVision devices to the latest firmware.
Then use the h.265+ CODEC, for minimal bandwidth.
And, set a sensible fps frame rate e.g. 10fps or less.
If you direct-connect a monitor to your NVR, then within that user interface it will confirm the bandwidth used/available.
One final caveat - I have on a couple of occasions seen weird issues with home-made / installed cables (that give this symptom of not being able to get max. resolution), if your issues persist, please bring all four cameras local to the NVR and connect them using short shop-bought cables just to see if the issue is still present.