linds_41299 This is the right forum to ask these questions. And the immediate answer may be simple: you can repair instead of updating to get the fully-updated version without needing nearly the free space available on the drive in question.
As for what's eating up the extra storage, that might be more difficult to figure out. What you can do though is poke around in File Explorer. Open a window, click This PC in the left panel, and see how much free and total storage is available on C. Double-click the C drive and you'll see a bunch of folders. Right-click each one and select Properties > General to see its size. If you see anything suspiciously large, open it and check the sub-folders until you find the reason, whether it's legitimate or not.
Your computer will have some hidden files and folders that take up space, the page file probably being the largest. This is fine and normal. The question is about everything else.
Feel free to share your findings with me, or ask any questions about the process.