Nature, of the beast. The first pump, in our Mh was near silent. The one they put back in pulses like others. A loop, of flexible, or rubber water line helps cushion it. If it is water hammer, they make a fitting or piece of pipe with an air cushion to eliminate it. A plumber knows what I'm talking about but I can't think, of the name, of it.There are other types, of pumps than diaphram. I don't know why they don't seem to sell them, for RVs. Of course it would probably mean pressure tanks and valves but perhaps not.
Maybe some, of the Prevost and others, have a better idea.