Is this really a mystery? MD kids are 3 (or 4) months older than NY kids. That’s simple, but given the different age cutoff dates, these are the best/worst case scenarios for true on age kids in MD vs NY. Your view of best or worst depends on your state.
Assume NY cutoff is 12/1 and MD cutoff is 9/1.
Holdbacks and special circumstances not accounted for on either side. Consider them equal for both (unless you know the actual statistics? Honest question. Yes it happens, but does anyone have actual numbers or is everyone always making assumptions?).
Youngest 2024 in NY is born on 12/1/06 Oldest 2024 in MD is born on 9/2/05.
(MD player could be up to 15 months older than a NY player)
Youngest 2024 in MD is born 9/1/06. Oldest 2024 in NY is born 12/2/05.
(NY player could be up to 9 months older than a MD player)

If you want to muddy the water, yes, throw in some holdbacks. However, most holdbacks are not the absolute earliest possible birthdate for their “revised” grad year.
Maybe whoever is griping about NY - MD ages should petition the youth lacrosse world to switch to age-based as it should be. But until those pigs fly, maybe just start a league where kids can play only kids with their same birthdate. And while you’re at it, buy trophies for all participants, hire unicorns for referees, and don’t bother keeping score. Wouldn’t that be fun.
-MD with on age kid