I buy most of my pressure washing car stuff from here:
https://www.obsessedgarage.com/collections/pressure-washing
Although I do not have a pressure washer from them (yet). I do have the high end foam cannon, and it works very well.
I cobbled together a custom pressure washer from some parts I already had: 5-hp 3 phase motor, VFD (variable frequency drive) and added a pump from General Pumps. I only did this because I had the existing parts and getting the pump and unloader was just a couple hundred dollars (open box special).
I am considering buying a pressure washer that I keep on the RV, the “Active 2” found on that site.
If anyone has a good solution for ceramic coating, something that comes with enough product to do the entire coach without costing and arm and leg, I’d be interested in knowing about it.