Google's Gemini AI is supposedly being developed in-house by Google's developers. Apple Intelligence is using ChatGPT as its base, and will eventually get the typical Apple-branded final release. Gemini is still really new and will be getting all kinds of changes. Apple Intelligence is even newer and still just beta.
So at this point compare Google's Gemini with OpenAI's ChatGPT, and keep in mind this is a wild time for AI development. Ranking one over the other is based on variables to come.