Copyright doesn't have anything to do with determinism. It existed in a pure analogue world before computers and if you had implemented your neural net in a fun

Copyright doesn't have anything to do with determinism. It existed in a pure analogue world before computers and if you had implemented your neural net in a fundamentally non-deterministic way (such as an analog neuromorphic neural net of some sort), it wouldn't make any difference one way or another. A human artist with no computer whatsoever and only their brain and basic writing (or painting) implements can break copyright just fine by writing out (or painting) copyrighted works from memory, then distributing them. It's the PRODUCTION side that is the copyright infringement, not the observing side.