The current system of corruption doesn’t allow you to restore the monolith back to uncorrupted (corruption=0).
Until reaching corruption level 11, there are no negative Shade of Orobyss nodes spawned. And once you reach 11 or greater, there are not enough negative Shade nodes spawned to allow getting corruption back to 0.
This can cause a problem for unaware players when they inadvertently end up corrupting the timeline before completing the final boss story echo and increasing the boss damage and health and making it difficult to progress past that timeline.
Please provide a mechanism, either via negative corruption shades or other method, in order to give the player a choice to reduce corruption back to 0.