A potential fix might be to not open the transfer portal until January 2nd or after a team's bowl game. I don't know if it would work, but it's something I hope the NCAA would consider.
I brought this up in another thread with the same idea but....
Here's why it won't work.
Players that enter the portal have to find a new home AND start school at their new home in the Spring (typically 1st or 2nd week of January). Why? So they are part of the school, can play in spring ball, and learn the new systems before the fall.
Moving the portal until after the bowl games doesn't provide enough time for this transition.
Sucks, but that's the big drawback.