Alston wasn't really about NIL. It was about schools providing additional benefits to a student.
The current NIL landscape is more a result of states like Florida, California, and others who had passed laws that made it illegal for schools to prevent students from profiting from their name image and likeness. The NCAA had vowed to fight those laws, but Justice Kavanaugh's opinion that was part of the Alston decision, was effectively a warning shot at the NCAA letting them know that future cases brought to court, involving student athlete benefits, weren't likely to go in their favor. His opinion isn't legally binding, of course, but it was a very clear announcement that the NCAA shouldn't push their luck.
So with Kavanaugh's warning in mind, and the first of the state NIL laws going into effect in July of 2021, the NCAA issued the instruction to allow NIL.
So, to answer your question, Alston didn't really set any rules for NIL. It was more for what types of benefits schools could provide. Theoretically, a state could pass a law allowing for students to be paid directly by the schools, but I don't believe any state has done that yet, and it almost certainly would be challenged by the NCAA.