Corona vaccines are just money makers for the vets. They are NOT considered core vaccines and I would never subject my animal to it. I suggest you find a vet in your area that is AAHA accredited. They ascribe to the core vaccine protocols of the National Veterinary Societies.
As for vaccines two weeks apart. Only if they are different vaccines. Ie - Ph'nx just got her Dist/Parvo, in 2 weeks will be getting her Rabies, then 2 weeks later her "adult" dist/parvo.
You are wasting your money if you are giving say, a dist/parvo then in 2 weeks boostering it. Not only wasting your money but overdosing your dog, IMO.