You could just remove the different effort dice all together and just use averages. Especially for kids.
obviously if you get a +1 for wpn effort, it’s now a 4.
There are cons for doing this as some people enjoy rolling for damage. but if all your kids needed to roll is a single d20, the game would flow so smooth.
I understand the averages I put are rounded down but you could round up if you wanted to make things die a little faster.