Hello Everyone! I Was Wondering, Do I Need A Santuko Knife And A Chef’s Knife? Any Help Would Be Nice.?

I have a block set bought off of TV, I don’t suggest doing that. I am now building a set. I just bought a 7″ & 5″ Santuko set of Calphalon knives. I am nowing looking to get the 8″ Chef’s Knife, 5″ Santoku, 6″ Utility and 3.5″ Parer all in a set. Do I need it or can I manage with the 2 Santuko knives. Yes I know that set has a 5″ Santuko. I will probably give it as a gift to my mom if the set makes since. Thanks again for any and all help!