Studies didn't find benefits either, it was mostly non results. More people means more people, they work and consume services at about the same rate, what matters is just how the new people distort the ratio of different kinds of people not that they are more people.

More people means there is more competition for housing until more supply is built though, so housing prices tend to go up from immigration. That is good if you wanna sell, bad if you wanna buy or rent.