If you can’t hit redline when at WOT with your current prop, going up pitch won’t help. I have two props for my 20’ aluminum bay boat with a 115 pro XS ct, a 4 blade 17 pitch and the same prop in a 19 pitch.
The 19 pitch is what I use in the spring and fall for fishing. It takes a bit longer to get on plane but has a higher top speed and (more importantly) a lower rpm at the speed I want to cruise. This is with 1-3 people on the boat. As I add people/weight it is a noticeable difference in getting on plane.
I put the 17 pitch on in the summer, when I am pulling a tube and tend to have more passengers in the boat. I’ve never even tried to pull the tube with the 19 pitch.
Aluminum props can help save your lower if you do something boneheaded like strike a submerged rock jetty on plane. I’ve seen it save a boat lower once.