I installed MS Flight Simulator 2020, but then realized that I needed to clear out a lot of space. 1 week of deleting later, I finally got the amount of space needed, but Flight Simulator does not seem to realize it. How can I finally install the game?
It looks like you've freed up enough space for the download, but not for the installation. Once a program is installed on your device, it has been decompressed, copied, moved, and so on, taking up more space than just the raw downloaded files.
According to this Microsoft Graphic, you need at least 150 GB of space for Flight Simulator to be installed.