If quantum mechanical outcomes are random, which we (smarter people than me) are quite sure that they are, universe can't be deterministic. If a system has a random element in it, the outcome of the system's products/procedures will be, at some level, random as well.

That doesn't mean you can't predict almost anything based from the non random elements of the said system, but it does mean that it's not absolutely deterministic. I'm not saying
"BECAUSE QUANTUM MECHANICS EVERYTHING IS RANDOM FREE WILL EXISTS WOOOO",
because firstly I don't understand quantum mechanics, and if someone here says they do, ignore that person.

But if there is a random element to our universe, absolute determinism doesn't apply (that's at least how I understand it.).