It's probably futile to argue with you but have you considered maglev trains?
I can overcome gravity all by myself just using my muscles to lift things. That doesn't mean that I've manipulated gravity in any way.
I'm really shocked that I seem to be the only one who groks the difference between observing a natural physical force and actually understanding it well enough to manipulate it and generate it at will. We cannot generate gravity. We can generate EM fields, and we can also generate nuclear energy by splitting or fusing atoms (which means we're manipulating the nuclear strong force, to an extent).
There's your misunderstanding. Gravity is not a force. The force is merely the effect you observe on your specific instrument. The cause and substance of gravity is not explained solely by its effect (force), and the force is not what generates gravity, et al. And, in fact, mass is not the only thing that generates gravity. It's flux of energy density. So it boggles my mind that no one considers EM energy as a subset of the energy that can produce "stress on space".
Conclusively, you've made some assumptions you don't realize resulting in an uncontrolled thought experiment. When terms are defined incorrectly, questions using those terms become wrong. If the questions are wrong the answers also always come out wrong.