D3 Amount of merit $, can you get a full-ride?

It can be done at the Div I level, even high level FBS programs but it falls to the student to make it happen. A friend of mine from HS was a national champion in football, All American, and high draft pick. He turned down the NFL for med school. We lost touch after that but surprised me 15 years later when I was visiting an uncle in the hospital after surgery and in he walked as the specialist treating my uncle. He and my dad (mainly my dad) had made the connection but wanted to surprise me when I came to visit.

I had plenty of teammates that were high level FBS school olympic sport that went on to med school, law school, dental school, etc. and they made it work with 12 hour days (lifting, am practice, class, pm practice); again it can be done you just have to be prepared for it.