Some formations should give an advantage to the defense and others to the offense.
Testudo vs missile firing.
Phalanx similar but less protection and some attack 2% more maybe
Close formations should have bonuses against falling arrows and other projectiles.
Syntagma and Anticav would be bonus to the attack against cavalry.
Closed formations should penalize movement and open formations should favor it.
The Persians were to have a unique formation, which would serve as a shield and barrier to the enemy of archers.( Protect the archers) It would be a composite formation.
https://archeryhistorian.com/persian-archery/#:~:text=Persian Archery %26 Battle Tactics&text=They would release arrows%2C and,units would form their lines.