Gravity is the curvature of spacetime. One of the consequences of this is that the dipole moment of the field is constrained to be zero. This poses a problem for gravitational engineering: all of our electromagnetic technology exploits the electromagnetic dipole interaction, but while there are positive and negative charges, there is only positive mass and energy. (Even anti-matter has positive mass.)
So you won't find anti-gravity, artificial gravity gravitational wave communicators, or the like. The field just doesn't work that way.
I know the theory, and I don't pretend to understand them as it is not my field, but I have never met anyone who claims to know everything about gravity. If that were the case, why are we still using rocket propulsion and making a bird that has to fall out of orbit and endure reentry heat to land like a jumbo jet.
Whatever the next theory of gravity has in store for us, it can't repeal the conservation of momentum and energy. We use rockets because, in order to accelerate, you have to have something to push against (conservation of momentum). Things heat up on reentry because the orbital energy has to go someplace (conservation of energy).
When my imagination is turned on, (happens occasionally), I alway get this feeling that we are not seeing the tree clearly because the Forest is blocking the view.
I understand that conservation of energy is a given, and that the tremendous amounts of energy needed to mimic and create artificial gravity may theoretically prevent it's creation. But i cannot get over a feeling that I have always had, that tremendous amounts of literally free energy have been at our fingertips, yet we cannot realize it.
So I continue to try to find out where, and what it might be. If found, conservation of energy may well be a problem no longer.