Thank you for providing some more information as well as some screenshots. Regarding your second screenshot, it seems like setting the height attribute ensures that the polygon will be visible. There seems to be a consensus among community members that this is the correct way to ensure that the polygon is visible. As for the color accuracy when viewing the polygon in 2D, @11179 came up with a great solution that he outlined in the following post.
The key is that both the height and extrudedHeight affect the color of the asset. @11179 feel free to interject here with more suggestions for @zhouhai1. Let me know if there are any lingering questions or concerns!
-Sam