Choir directors don’t fix a section by making one singer louder. They get everyone hearing each other.

Volume is rarely the problem in a group that sounds wrong; listening is. Push one voice up and the blend gets worse, because the others stop adjusting and start competing. The fix is making everybody aware of what is around them, after which the parts find each other without anyone being told to try harder. Most teams that feel out of sync have a fault of the same shape.

If your group is pulling in different directions, stop adding effort and make them aware of each other. Have people say what they are working on before they start. Then ask who they need to check with.