God could have controlled the behavior of evil spirits, why not?

The evil soul belongs to Satan. God allows evil in the world, so every believer will be tempted. God wants saints to overcome evil through truth and rely on Christ to make us grow spiritually. Many times, saints test us through the temptation of victory. The kingdom of God has to go through many difficulties, and saints have to constantly overcome the disturbance of evil spirits before they can gradually approach the point of sanctification. Without these temptations, saints don't need to overcome anything, and the value embodiment of saints is weakened a lot. Eve was seduced by Satan and plunged the world into sin. Without the initial temptation, how could Adam and Eve abuse their freedom, and all mankind would not need redemption. It is precisely because evil spirits devour our souls that we cannot use our freedom correctly because of sin that believers have the power of the Holy Spirit to work on us and save us. It also indirectly tells us that since evil spirits exist with God's permission, only the Holy Spirit has the ability to fight against evil spirits, so everyone needs God's spirit as a spear and shield to resist the corruption of evil spirits.