What you’re getting at is known as the “risk free rate,” or the risk premium of leaving your money with another entity for a period of time. US gov’t treasuries carry a risk free rate; you’d just buy treasuries.
The two aren’t mutually exclusive and the roles change as the kid gets older.
When they’re newborns you are focused totally on providing: they can’t feed themselves, change their diapers, or bathe themselves.
When they get older they can do those things but then start having questions about the world and girls and faith. That’s when it really gets fun because you strengthen the bond.
So you’re always providing for the kid. Being there is the tougher part.