I’d protect the willingness to break forward and coach the balance around it.
When possession changes, it is natural that players see space ahead and want to join. The problem is when everyone makes the same forward movement and nobody is connected to the ball if it is lost again.
Give the players one simple reference: “As we attack, who is keeping us connected behind the ball?”
That player does not have to be the same person every time.
A transition game with quick counter-attacks works well. If the attacking team loses it, the opponents can score immediately in two target goals behind them. The players start to feel why balance matters.
At U13, I would not tell half the team to stay back.
Teach them to recognise that a good attack still needs a structure for the next moment.
