That’s not completely correct. In particular, the mini resolution corresponds to the Display Zoom options on current iPhones, so applications are still expected to support them, not to mention that iOS will support the mini models for 2-3 more years to come.
In addition, the outer screen of next year’s iPhone Fold will be shorter than the mini, so applications really need to be flexible here.
I don't understand anything of what you're saying. But I do know that it was quite noticeable that most applications expect a bigger screen on small iPhones. Most UI elements are either too small and hard to use, or taking away too much space feom elsewhere.
There's nothing you can do with scaling here, if apps are made for big screens. It is a feedback loop. It would require a whole new ecosystem to break out by now. Impossible.
They might technically support them, but no one tests them properly and they’re certainly not a good user experience. I’ve personally made apps where I have never tested them on such zoom levels if I’m perfectly honest.
In addition, the outer screen of next year’s iPhone Fold will be shorter than the mini, so applications really need to be flexible here.