Your entire world view and belief system is based on gravity, an unproven theory.
It is a theory in that they don't know how it interacts with space time yet.
It is proven that gravity exists.
There really is no proof that gravity exists. Density and buoyancy explain why heavier than air objects fall.
Oh gravity exists, regardless of your flat Earth mindset that wants to discredit it.
Have you ever wondered why the air thins out the higher your altitude? Yes, you can thank gravity.
In your world the air density, and air pressure, should remain the same all the way from the surface of the Earth right up until it reaches your dome. The reality is it doesn't. A prime example of this is the balloons you flat Earthers like to send into the sky with cameras to capture the "flat horizon". This is the reason the balloons expand the higher they go until they finally burst at high altitude allowing the camera owner to retrieve their camera after its fall (due to gravity). Again in your world, the balloon shouldn't expand at all but simple float up until it touches the dome.
Why would the air pressure remain the same, earth still has a pressure density gradient. Either this is a weak attempt at a strawman argument or you're just soft in head. Everything can be explained with the force ultimately coming the domes trillions of volts.
Still on the "static electricity replaces gravity" bandwagon I see.
Okay, let's pretend that an object's charge is the reason that it gravitates (pun intended) towards either the Earth or the dome. Negative charged objects would move one way and positive objects the other. In the case of the air, this would cause a high concentration of molecules close to the Earth and close to the dome, with a large void in the middle.
Now an area void of molecules, or matter in general, is a vacuum. We define the vacuum above Earth as outer space, so the first problem with your theory is you now have to acknowledge the existence of outer space, something flat Earther's generally don't believe exists.
The next problem you have is you claim about density and buoyancy. When you refer to density and buoyancy like you have, you're referring to gravitational forces affecting an objects acceleration. We know from observation that objects of different mass will accelerate at the same rate towards Earth. If you replace gravity with electric charge, as you're trying to do, you'll find that objects with different mass but the same electric charge will accelerate at different speeds, something that falling objects do not do.