I'm making tomato sauce and it's too acidic, help!

I think it’s the type of tomatoes I used… just regular crushed canned tomatoes. What do I need to reduce the acidity? (I think I read that a carrot will help… anything else?)

I started the sauce with EVOO, garlic, onion, crushed red pepper flakes, salt and pepper… added tomatoes, a little oregano, about 1 tsp of tomato paste and some lemon zest. It’s still lacking in flavor.