That's what I meant by "if you're using some API you have no control over, anything could happen." OpenAI could offer access to a fully deterministic version at a higher price point, but they choose not to and there's nothing you can do about that.
If you'd read the source you linked you'd see that no, the system is inherently non-deterministic. They cannot sell you a deterministic version of GPT-4. There is no such thing. They could sell you a deterministic version of some other inferior model.
FYI, your source is medium-walled blog spam of https://152334h.github.io/blog/non-determinism-in-gpt-4/