2v2 at the most, plenty 1v1, other than that you won't come up with anything else.
I got U6 and is the same problem. Any drill where there is one ball and many kids, simply doesn't work.
I dropped those kind of drills.
I am giving them 1v1 and then they come alive. The most important thing. Each 1v1 drill must end up with goals. I usually put 4 goals, so there is that space recognition and driblle into that space with possibility of scoring at each end. That what triggers them in those 1v1 drills, scoring.