When a Supreme is using their power to reach the limit of the light side in one aspect, such as attack power, their defense and speed will be lacking in that moment.
It won't be a problem if the enemy is a single Supreme. That Supreme will be busy resolving their attack. But another enemy will be able to take advantage of their exposed weakness when they are busy with someone else.
The dynamics between Supreme Origin gods is still true even though his pursuers are not true Supreme Origin gods. They are just Sovereigns of law who have received the power of the Will of the realm in order to repel the invaders.
That is another thing that no one knew that the Will of the realm could do. Even normal children of the plane are rare. Not many know that a transcendent can be boosted to the power of an Origin god thanks to the enhancement of the Will of the plane. So knowledge about the children of the realm is rare.