have you read the books? there is a passage where Duncan (it might've been miles teg, it's been a second) acknowledges that no one in the dune universe actually knows how space folding works. they know what the equations are, but not how they actually function
have you maybe considered that the information they have been fed differs from your own?? they are not horrible people, they have just been the recipients of propaganda for generations
electromagnets also work as the earth has a magnetic field. a pair of reaction wheels can be rotated (which yes, adds complexity) opposite directions along an axis perpendicular to the axles once they have reached saturation, effectively resetting the reaction wheels
but imagine how incredible physical controls for navigation could be