Prop and setup...confused

I have a Venom 17 with a 115 Johnson. The motor sits on the transom as low as it can go. I have not tried moving it up yet. I have tried a raker 20, 22, and 24 prop.
20: quick holeshot, top speed of 48 mph, 5700 rpms
22: holeshot is good but not great, 52 mph, 5450 rpms
24: insanely fast holeshot, 49 mph, 5900 rpms

Shouldn't the rpms be lower w/ a higher pitch? Is there a different prop I should be using? Should the motor be raised? I want to get a few extra mph if I can.

I had one of those boats a while ago. stick with the 22 Raker.

What about engine height? Did you raise it or put a jackplate on?

No it was set in the middle hole no JP.

Without a jackplate to adjust the motor height for each prop, as each prop will be different, you are going to be all over the place. Look for the prop that will put you at or near your max RPM and maintaining good water pressure