Ok well I disagree that it is not a flagship. And the survey is not a joke, it is a reasonable survey that polls 5000 members of the iPhone market. And it is exactly what I would expect to see. Nothing surprising or unbelievable at all.
The iPhone mini is exactly what people said they wanted. An all screen design, with Face ID, and the latest processor and features, that was smaller than the iPhone X. And within the iPhone 12 and 13 lineup, the feature gap is really small across standard and Pro. So an iPhone 12/13 mini is a fully packed iPhone with all of the latest features found in the regular iPhone 12/13. Which itself is very close to the Pro models. Very small gaps. So the iPhone mini is a perfectly capable flagship phone sporting all of the latest things that can be had for $700.
But it doesn't sell. And here is the thing you need to understand: it doesn't even sell well compared to the standard iPhone 12/13. It is by all accounts functionally equivalent and cheaper at the same time, and iPhone 12/13 still outsells it 3 to 1. That isn't because of "features". The features are the same. It is because people generally do not want such a small phone, especially not at that price.
Given this, you have to understand why there won't be a mini Pro. If people are unwilling to opt for the mini instead of the standard, given that they are functionally identical yet at a lower price, then they will never pay even more for mini with Pro features. That's why it doesn't exist, and won't. And if reports are to be believed, the mini itself will cease to exist after this year.