I never said nor do I support all private schools competing at the 4A level. That is nonsense. I would disagree with that completely.
As for how to fix the issue, that is a tough call. I am not a high school sports administrator so I haven't looked into the multiplier system that other states use to analyze how it might specifically work in Iowa.
However, I would imagine it would be feasible to do an analysis of other states and then adjust that to fit Iowa. Perhaps I am wrong and there is no possible way to do it.
I believe there are many 3A schools that are 3A only in enrollment, but 4A in everything else (socioeconomic, resources, abilities, not having defined districts, etc...). I would imagine if certain high schools were truly interested in being the best they would have chosen to stay 4A and compete against Dowling, Valley, IC West, Bettendorf, and other top notch schools. Maybe not.
On the flip side, I believe there are many schools that are 4A in enrollment but perhaps 3A in everything else. Schools like Waterloo East, Davenport North & West come to mind. That is a harder problem to fix. Measuring available resources isn't always a realistic endeavor.