PFOF (Payment For Order Flow) doesn't necessarily means that customers get screwed.There's no statistical proof as they don't release the numbers.
But the fact that RH gets paid way more for order flow compared to competition tells you that they screw the customers the most.
Public Customer orders are the real deal for Market Makers. It's where they make the most of their dough. And they don't make money by screwing Public Customer (aka retail). They are making money out of them because most retail traders are losing money. Market Makers make money on the spread, by having quotes sitting and waiting to be lifted, and mostly by retail traders.

