you can literally just chop them up and boil them with spices, it works absolutely fine.

You don’t need all this fancy stuff (blanching tomatoes is insane to me, as is removing the skin: the skin is nutritious and makes the sauce thick!), just try a bunch of different things and see what you personally like best.
I like to fry up some diced onions and a couple cloves of garlic; then dump in the chopped tomatoes (i recommend one of these pull-cord chopping things, absolutely liquefies the tomatoes), a bit of vinegar (balsamic is always nice), and some spices (lots of vegeta) and let it simmer for as long as i can be arsed.