"If" everything is working properly, I would try removing your cabin air filter. If removing it noticeably increases your air flow there's your restriction. If its dirty then replace it, if its clean....yeah.
I've pulled the air filters out of a number of vehicles to test this. None were a newer Jeep. Some you didn't notice much, others it felt like you went from #2 speed to high. None of the filters were dirty.
My Tacoma makes very little difference.
As for modifying the system, the amount of work it will take will only change it a little.
Maybe someone else will chime in with a "Do this"