I would do the pro/rel system for football and basketball individually. All the other sports have underlying issues that really need to be addressed in a different manner as not every school plays every sport.
The big money is spent on football and basketball. Some schools throw all of their resources at one or both of these. Let those schools that want to be the HS version of 1980’s SMU do so. Under pro/rel, they will all end up beating up on each other.
On the other side, those schools that perpetually struggle to keep up or have really tough situations with support should be allowed to settle in a more comfortable alignment. Those kids deserve a chance to succeed too.
This is the natural way to let things sort out on their own. We have to stop forcing square pegs in round holes with the 5 classifications and the sheer madness of the Select/non-Select bullshat.