TBH the solution is to salt the pesto less and salt your toppings more, probably by just adding finishing salt after cooking the pizza. Also consider using a nonfresh mozzarella, which generally has more flavor. While the creaminess of fresh is nice, I find it to be way too bland most of the time.

This problem is the exact reason why I stick to pepperoni and banana peppers. They are inherently flavorful and salty.