You are mixing up two different mechanisms of action. Slowing or reducing damage vs effecting healing of that damage.

The early administration of the substance prevents or slows the cascade of damage. But, if that cascade of damage is not slowed, then that damage spreads and the injury is more intense.

You mention a lot of technical details. One of the concerns you missed is damage to the glymph system. Like the myelin sheath, the glymph system needs to heal. It clears the toxins just like the lymph system does in the rest of the body. It is thought to be slow to heal just like the myelin sheath.

That slow healing would suggest a reason for our brains being so hyper sensitive to stress.