There is no cheap paint fix for white diamond. First of all there is an extra layer of paint that need to be applied and they need to blend it much further across the panel to make it match. Pearls are always a challenge. That reminds me of the 80s when GM and Ford had paint coming off the trucks in sheets because it was not bonding to the new primers they were using.
I would think the dealer might do something about that.
And as far as I am concerned if a pressure washer takes paint off, there is something wrong with it to start with. Its not a fault of the pressure washer.