They do apparently earn a high school diploma:
https://en.wikipedia.org/wiki/Overtime_(sports_network)#Overtime_Elite
"In addition to receiving a high school diploma, Overtime Elite's educational offerings will place an emphasis on developing life skills supplementing traditional courses with those focused on financial literacy, media training and social justice advocacy."
Wikipedia lists 14 players on their roster, and one head coach. That's enough for one team. What's the plan? Is this team going to barnstorm? Whom would they play? (The NCAA stopped letting their schools play barnstorming teams over a decade ago, which is why you never see them anymore in NCAA exhibition games.)
If the plan is to create an actual league and to generate revenue by having these teams play each other and broadcast the games, it will require many more than 14 players and one head coach.
It seems there's plenty of investor money in this venture and there are some big names attached. I just wonder what the business model actually is to generate revenue.