If the electromagnet is an absurdly high frequency (which would cause loads of other problems, but let’s suppose), then the right magnet is always seeing the (essentially) static field from the left magnet. The left magnet is seeing (essentially) the instantaneous field produced by the right magnet slightly in the past, due to propagation time of the field. The phase lag between these two will mean that at a given moment the forces will not be balanced, so the system will move (momentum is being carried by the fields, so is still conserved overall), but the time average will still be zero, so your car will simply oscillate in place. Also, oscillating the electromagnet takes energy, so this wouldn’t even be a meme device. You’re supplying energy to produce motion. You’re just doing it in a retardedly inefficient way
