P factor comes into play when the prop is not 90 degrees to relative flow.
Some boats like my IP, have very little angle difference, and therefore would have very little if any P factor. And yet, they can have significant prop walk.
I believe the high pitched props exhibit prop walk more than flatter pitched props do, I think the high pitch
acts sort of like a paddle wheel
and "walks" a prop when there is little induced flow, IE almost no boat speed.
I know when I went from a high pitched prop that had a lot of prop walk, to an Autoprop, my prop walk essentially went away. An Autoprop when there is no induced water flow, is an almost flat prop with very little pitch
, it adds pitch as boat speed (induced flow) increases.
I think over propping is very common, My boat with the 17X16 that was on it would only turn 2600 RPM at full throttle (3600 is spec) it was so overpropped. If you don't overload an engine that is overpropped it won't damage it, just you have about 1/3 less usable HP than an engine that is correctly propped.