The shield over the APU and RAM should just unclip from the soldered in frame. The flat end of a spudger ([product|IF145-002|like these|new_window=true]) is the perfect tool for this job. You can see what I mean in this YouTube video. It's upside down, but you can clearly see that the mount for this shield is soldered to the board, but the shield is separate and can be unclipped from that.
[video|https://youtu.be/kOCE6gUtl7o?si=LaGyuJKgnbVxruLd&t=321]
As Dan mentioned, you would really only need to unclip this to inspect for liquid damage or if you bought it used and it looks like it was previouskly tampered with. I would absolutely verify in this case that it's not an issue with the display. Since it sounds like you're getting backlight, but so picture/image.