I don't think we have the same point here at all. First off, I don't think depression is a good measure of intelligence. But mostly, my point is that it doesn't make it less real when hormones aren't involved. Hormones are simply the mediator that causes that internal experience in humans. If a true AI had an internal experience, there's no reason to believe that it would require hormones to be depressed. Do text-to-speech systems require a mouth and vocal chords to speak? Do robots need muscle fibers to walk? Do LLMs need neurons to form complete sentences? Do cameras need eyes to see? No, because it doesn't matter what something is made of. Intelligence and emotions are made of signals. What those signals physically are is irrelevant.

As for giving it feelings vs it developing them on its own-- you didn't develop the ability to feel either. That was the job of evolution, or in the case of AI, it could be intentionally designed. It could also be evolved given the right conditions.