I've seen kits on line to add a loop of flexible hose between the pump and the stiff plastic pipe, which are supposed to reduce noise.
Pump Silence Kit
There are also RV specific accumulator tanks that are reasonably priced and might cure your pulsation.
Shurflow Accumulator tank
The other choice might be one of the smart sensor pumps that are supposed to be quieter and vary speed based on demand. If you google "RV water pump smart", you will hit on all kinds of retailers. Here's one.
Smart Sensor pump
Mine is kind of noisy and can pulsate if the kitchen cold tap is opened abruptly, and I thought about upgrading, but I guess I got used to it and forgot about it...