Generally, When I read physics and ontology on the same paragraph I slightly cringe. Not that it is bad to use it, but the implicit mathematization of ontology is what takes me back.
Let me tell you why, Quantum Mechanics is undeterministic solely due to the fact that the solution to Schrodinger's equation is a wave-distribution. That is, we get a probably spread of postional coordinates for a particle. On the other hand, for Pilot-Wave we have a wave fuction, which deterministically evolves. That is, given the initial determined input one can "theoretically" get a fully deterministic output for it; however, the uncertainty in Pilot-Wave creeps in with the initial input because of heisenberg's uncertainty principle. So, inessence, Pilot-wave is as deterministic as it could get, but the only problem is the initial measurement. That is, can we get a precise location for a particles? According to expirements and heisenberg, we can not. As for Quantum Mechanics, the actual developement of a system is essentially undeterministic. That is, it is dynamically evolving-until you get a measurement and that is where the wave fuction collapses and we get an acrual value. So this probabilistic evolution of schrodinger's equation is what gave rise to these whimsical interpretations of Quantum Mechanics like Copenhagen Interpretation and Multi World Interpretation. As it is quite obvious, the only reason we have these vastly different intepretations of quantum phenomenon is the mathematics.