Start making athletic scholarships a formal contract under consideration as being employees. All deals are a 2 yr minimum.
Either that or open the portal for the first semester, therefore making a player ineligible for second semester and have an active portal period from April 1 through May 31.
Exceptions being graduates, family emergency and coach vacancies for which entrance to the portal can occur outside the entry window.
By no means near a perfect solution but somehow this has to make more sense.