Which brand of prop are you looking at?

The pitch of any location along the radius is determined by what the mfg wants out of that location.

4strokes usually turn a prop more slowly than 2strokes. But there is nothing about running a prop at lower speed that demands the pitch at the tip be flatter or have greater AOA either.

The ones you've seen look that way simply because the mfg was getting enough lift out of the rest of the prop that he could use less at the tips. For the speed he expected each station to experience with the engines he thought would probably be spinning that prop on the airplanes that might be hanging behind those engines.

There are a number of 4stroke props that have very much greater pitch going out the blade.

Ain't no sound byte wisdoms large enough to cover prop details.