There not a lot of differences in the 4,5 or 7 step deliveries. It just more steps that you take. Everyone has different deliveries styles and you should want feels good to you but I tend to see that the more steps that you take, the more speed you put on the bowling ball but that depends on where you are standing as well so it’s hard to see a differences.
I use the 4 step deliveries because I feel with less steps and can do the same shot over and over and the less steps and things you have to do the better overall but its total up to you how to bowl. I see people do a 2 step deliveries and it works for them.