I'm surprised that no one is discussing electrohydrodynamic engines for this application, for example as used by https://en.wikipedia.org/wiki/MIT_EAD_Airframe_Version_2. These don't have the same limitations as rotors do with vectoring relative to high speed gas flow. Most of the ones which have been built are small, but that is not an intrinsic limitation; mainly its the battery weight that is the limiting factor.

Of course, the whole idea of electric field is depending on the battery breakthrough, but assuming you have that and want to go supersonic, I'd figure you would go EHD.