Why did i lose so much storage space?

I downloaded the following things, epic games launcher, a few small drivers, windows 10, discord and I'm currently downloading fortnite which is currently loaded with 25GB (up to 44GB). All this is not even 50GB…

why were additional (plus fortnite was only half downloaded) 50GB consumed?
the extra apps cost a total of just 2GB

I'm assuming cache memory for the Fortnite thing.

What is cache?

Memory that is kept free. You only download so and so much. But all apps and updates need extra space which is then reserved

Definitely has something to do with it, I think too.

With TreeSize you can determine where the most storage space is used:
https://www.jam-software.de/treesize_free

But be careful: don't just delete it. Every directory has its purpose and its purpose.

Thank you