Ultimately separating the network with its own access point will be the best practice for the cameras. This avoids issues with router network optimization features, bandwidth, network key changes or other ongoing updates you might make.
The issue you are describing though sounds more like a local camera issue though. If it always and only occurs when the camera kicks on the IR nightvision, have you power cycled that camera?
How long is the power cable for that camera now?
Details on onboard SD card storage can be found in the link below:
The max SD card size is 512gb. The V622 does not support onboard storage at this time. The V515 and V724 do.
See guide below for estimated storage based on selected settings and SD card size.
