Every parent I know takes away their kid’s electronics when they get bad grades. The belt, not so much.
Before a certain age, they shouldn’t even have electronic devices. It rewires the brain in ways we don’t fully understand and the fruit of that is still waiting to fully mature many years yet down the road.
The belt not so much.
My dad loved a board my brother had made in shop, 1x4 with leather grip, even had 5 holes drilled to avoid wind drag when he swung it. Got beat all through jr high and high school for every D. They felt beatings were the best way to improve academics. When I was a dad faced with the same issue my wife and I got a tutor to help my son.