NS Panel screen settings

Is there a way to keep the screen on all the time on a NS Panel?

You can disable Energy-saving mode within the eWeLink app:
NSPanel > Device settings > Screen settings > Energy-saving mode > Energy-saving mode > Toogle to off.

After that the screen only dimms after the period set at the NSPanel itself at this location:
Homescreen > swipe from top to bottom > Sleep

When Energy-saving mode is enabled the above mentioned timer turns off the screen completely.

When in energy saving mode will the screen turn back on after the scheduled time to turn off?

Indeed. When it is turned off it dimms the screen instead of turning off.