One of the first things I figured out after making that jump was that the constraints involved in making an app run smoothly and be just as comfortable to use on something like a 1st gen SE - which is what I used myself, from 2016 through most of 2021 - can't be supported alongside the capabilities and display real estate provided by current models, without an indefinite expenditure of costly developer effort that just isn't economical in supporting a use case that's relevant to something like sixty users out of every thousand.
We've been through this before, with the PC revolution. Things settled down on that front, GPUs excepted, right around the time smartphones became a thing. The complaints are more or less exactly the same, and so are the reasons they receive little of consequence by way of response. None of which is to say you should upgrade your phone if you don't really want to, but - speaking as one who has done so himself, prior to having discovered firsthand why things are the way they are - yelling at the entire industry to change how it functions at a fundamental level has much more of King Canute about it than of any really worthwhile expenditure of effort.