Best way to get more money is to schedule a meeting with the Head Coach.
When you meet you do not say I need/am worth more scholarship money. What you do is ask about expectations and what you can do during the track season to earn more scholarship for next year (scholarship contracts are a year long).
Depending on the school and approach, you may be right, and the coach is happy to have you on less than they usually pay. Or, you may come to the realization that things are cut throat at the top of DI, and you should be happy to have what you do.
The transfer portal is neither good or bad for athletes, but I do think it has concentrated the scholarships available into fewer athletes. Gone are the days where guys sign for a small scholarship, and run well but don't get increased. If money is important, and you are running well, someone will pay you.