You're confusing quantum trajectories for classical ones. The latter are what we use in path-integral formulations, and constitute a single path through spaceti

You're confusing quantum trajectories for classical ones. The latter are what we use in path-integral formulations, and constitute a single path through spacetime. No such path exists for quantum states, since that would be a local hidden-variable theory (which has been experimentally ruled-out). Trajectories of quantum states are well described here: https://arxiv.org/abs/quant-ph/0302080 https://arxiv.org/abs/quant-ph/0302080