Large scale coordination during pre-modern warfare was effectively impossible. The battlefields would often stretch for hundreds of meters or even a few kilometers and it was too chaotic to see anything once in the heat of battle. Generals could issue some local commands, especially if they were at the head of a cavalry charge, but only the officers and bannermen leading a small formation could exert any real control over their soldiers. A general signaling ranged combatants is just unrealistic.

Your second point is spot on. Infantry formations don’t generally charge the way we think of charges - they were rather slow, controlled forward movements with weapons and shields lowered. otherwise the first soldier to trip or take an arrow would take down the entire formation. No one ever really pitches battle with their infantry starting in range of the other army’s archers so there’s never really a clear opportunity for a volley.

Cavalry charges are a bit of a special case because they’re especially vulnerable to archers, but they’re also the group most capable of avoiding volley fire. Cavalry charges don’t run into soldiers, they train for coordinated feints so they can quickly change direction unlike infantry. When attacking cavalry, archers generally want to have random fire to increase the chances of bringing down a single horse, which often causes enough chaos to break the charge.