This is a hot take which is in line with some of the extreme right-wing positions in Germany. For a more balanced view of the impact of the immigration to Germany, see https://www.aicgs.org/publication/burden-or-blessing-the-imp...
In short, what caused the increased food and housing prices was government spending leading to inflation; immigration was only one of the causes of this spending (the financial crisis in the southern European countries was another.) The expected outcome on Germany is a net-positive one.