There is a connection between gravity and electromagnetics, but it's mostly through the stress-energy tensor giving photons momentum (and thus gravitational pull) but to use an EM field to measurable gravity you need absolutely insane amounts of energy.

You essentially need the literal inverse of a supermassive nuclear explosion (almost like a small star), because the gravitational effect of energy is equivalent to the gravitational effect of the mass which it would form if bound, and given E=mc^2 and the fact that nuclear bombs are small enough to barely have measurable gravity then the math means you need truly insane amounts of energy. (unless somebody can figure out a cheat to create directional pull with much less energy, but I strongly doubt it)

It's more plausible that somebody would be able to scale up "optical tweezers" to move large masses (directly depositing momentum of the energy field on an object) because that no longer involves the E=mc^2 equation, but it would be even more complicated by a HUGE factor than building the type of large supercooled electromagnets which already can make humans hover (due to water in the body being diamagnetic)

No centrifuges create g-forces. The forces you feel in a centrifuge are actual g-forces.