Interesting hypothesis, but I am also a Midjourney user.

Let me try to answer in an ELI5 fashion:

You know how you can ask ChatGPT the same thing 3x in a row and get 3 completely different results? Google's basically the same and has been for a long time.

If you and me both ask for something hyper-specific, we'll see the same results. But the more generic the search term is, the more hyper-personalised it gets.

In some ways it makes sense, for example we shouldn't see the same thing when we search for "restaurants" as we're unlikely to be looking for restaurants on the other side of the world, in many other ways it's annoying and counter-productive.

I oversimplified. :) Main gist is that SERPs are personalized and based on your targeting profile which makes the results non-deterministic, as we're experiencing. Google is the only entity who will ever truly know.