How could I know how much of a line (in %) overlaps another gameObject?
This is the 2D forum which isn’t related to features like the LineRenderer. That said, a GameObject is a container of components so doesn’t in itself define an area or volume so without you being specific on what you’re really checking for overlapping it’s impossible to say. 2D/3D, Sprites? Meshes? Colliders?
Please take more effort in posting relevant information when asking questions to save other devs having to ask questions to determine what you are asking.
Images, videos etc.