You can see on this page that the deaths for flu + pnumonia is 41k, for flu not including pnumonia its the 600 figure:.
https://www.cdc.gov/nchs/fastats/flu.htm
The policies for listing covid ont he death certificate is generally different for listing Flu. Not sure how the policies have changed recently but back when I was actively a part of this we were required to list COVID as cuase of death regardless of if it is the primary cause or not. They may have changed that policy recently of course, not sure.