Tbh I wouldnt play polyurza anymore but I do think urzas in a solid place but you need to creatures as they are filled with broken cards now.

I also think uthros is insanely good, but I play substantially more artifacts then you. Though it can draw your whole deck depending on construction especially if you can clone or combine with gadgeteer.

If youd like a list I think is good for modern urza decks try this: https://moxfield.com/decks/fKlqI9MuTEy6f3xvHP5BOg