Interesting stuff. For those who are unfamiliar and want to skip the part where you try to determine whether electrogravitics and gravitoelectromagnetism ( GEM ) are the same thing, they're not. The former misrepresents the effect as antigravity, when in fact, it's ionic. However in reviewing a number of other articles it seems that gravitoelectromagnetism is being conflated with electrogravitics, so caution is advised there. GEM itself appears to be a serious area of scientific study. But there are some issues to consider.
The first issue is what is meant by the term "antigravity". If we're talking about a force ( any force ) that counters gravity, then airplanes and balloons also work on antigravity. So there remains the question of what exactly it is we're referring to when we say 'antigravity'. GEM doesn't really refer to anything concrete. According to the literature and scientific papers, it is an analogy that attempts to describe gravitational effects similar to the way EM effects are described. We know EM is associated with particle physics by way of the electron and positron, but those particles alone don't explain gravity. A graviton has been theorized, but none have been found.
The alleged discovery of the Higgs Boson remains controversial, and contrary to what is often assumed, it isn't the 'cause' of gravity. Rather it's theorized to impart mass, which is related mathematically to the presence of gravity. Essentially what we're still dealing with is a "fundamental force of nature", meaning nobody knows exactly what gravity is composed of ( if anything ). It just exists as a phenomenon of nature that is described ( as opposed to explained ) by mathematical models that outline it's relationship to other things, particularly massive objects.
On the idea that gravitation has a limited range, there is a difference between the claim that gravitation has a limited range, and it being cancelled out by some unknown opposing force, be it dark matter or 'actual' antigravity ( whatever that is ), and the illustration in your post makes that readily apparent. Great post. You always make me think! Here's another paper you might find relevant:
Gravitoelectromagnetism: Basic principles, novel approaches and their application to Electromagnetism ( PDF - 2016 )
