CHiEE, welcome to the website. I don't think I can add much to Clive's excellent advice to you. I never make much sauce from scratch, as your heart seems to be set on, so many of us can't be of much help to you there, but maybe there would be more tips in the pizza sauce section. From my many decades of deep dish pizza eating, if I walked into the kitchens of most of the classic deep dish pizzerias, I would find a lot of cans of some great fresh tomato products and most don't bother with a cooking process. But I will admit, that many of the great old-fashioned thin crust mom and pop shops did cook and concoct some great tasting pizza sauces.
Unless you are dead set on only working with a homemade cooked sauce product, I would suggest trying for the first few times using some high grade tomato products that many have recommended here first. And then work further afterwards on developing your ideal sauce from scratch (if you'll ever want to go back -- but some are irrevocably committed to natural . . . etc. . . I realize).
As to the excessive liquidity problem, I've written comments about that many times. It is difficult, of course, to diagnose the dilemma from afar, but the two greatest sources of such in my experience has been . . . first the sauce. It should be drained first -- at least all canned products -- for just a short while (est. 10 to 30 minutes max.). Then the cheese . . . fresh mozzarella is great tasting BUT can easily lead to a soupy pizza. Suggest use of a dryer mozzarella or cheese. You hadn't mentioned anything in regard to the cheese you used. The classic deep dish pizzerias do NOT use fresh mozzarella you realize (but I occasionally sneak some on).
The toppings can also be a contributor to the liquidity problem, esp. freshly washed vegetables. Sometimes the sausage or pepperoni can have too much fat in their mixture, too. But am kind of reaching out in the dark as I and others are just not seeing the whole picture and only hear the "sauce" issue from you.
Among the best canned tomato products to use for deep dish pizzas in my experience has been Lou Malnati's tomato sauce, 6 in 1, Pastene's, Muir Glen, and a few others that I can't recall at the moment. One of my favorites had been the combination of 6 in 1 with some small diced tomatoes from Muir Glen.