The hardest part of making good pizza is the dough. Most people who judge pizza don’t know what to look for. You can impress an amateur palate with good sauce and cheese on mediocre dough.
In America, Bianco di Napoli tomatoes are amazing. So too Stanislaus California tomatoes. Even the cheapest places use Stanislaus (they have premium and pedestrian lines), so rarely are tomatoes problematic (or sauce by extension unless it’s doctored with too much sugar, salt, pepper, spices, or herbs).
Similar with cheese. Most places use Grande. Some use Polly-O. There are smaller producers, like Pecoraro Cheese in Brooklyn (great) and BelGioioso Cheese (who I’ve partnered with in the past, and whose cheese is fantastic). But even places using cheaper mozzarella still use “real” cheese.