I’m not sure what “false low digital noise” exactly is.
Your top layer track and bottom GND plane looks like capacitor. Your track and top GND plane have very little surfaces seeing at each other. You can set top GND zone clearance intentionally bigger (like 0.5mm).
In my PCB I have linked in my previous post you can find something (see top left from main IC) looking like a wire ended with vias (it is not the only one there). And I said all vias you see are GND. So it is not the signal line traveling here. My intention was to shield fast output signals from slow input signals.
If you read and understand all articles I have mentioned here:
and here:
you will have knowledge enough for most PCB designers.
Having continuous GND plane is mainly important for return paths and not connections. Connections could be done with tracks.
If you will solder your PCB yourself GND at top is not needed (bottom should be enough). If it be automatic assembled than having comparable amount of copper at top and bottom is important to avoid bending the board during reflow soldering.
In my opinion GND plane is always good from EMC point of view, but sometimes not good from other points of view (may be even signal integrity).
Around 2000 I have redesigned PCB that originally had no plane at all and suddenly OpAmp begin to oscillate because being loaded with too high capacity.