What are "regular bombs?"

Are these dumb bombs dropped by a bomber aircraft? That would require aircraft to fly over to Moscow without being shot down. Ukraine doesn't really have many (any?) bombers. These long-range missions couldn't be done by fighters.

Or do you mean missiles? What kind of missiles? Ballistic missiles? Cruise missiles? Which missiles with the range necessary to reach Moscow are you suggesting they use?

Or do you mean drones? These are being used, but Moscow is far for drones to reach and has a decent amount of air defense systems in place.

Generally speaking the USA is able to bomb countries like Iran with relative impunity is because they attain air superiority. One of the defining features of the Ukraine war is that neither side has been able to attain air superiority, thus actual aircraft have played a limited role. Instead the air war has been fought using drones and missiles, not bombs.