Things that you can try to clean up first are the recycle bin, temporary files, browser caches, and old display drivers (looking at you Nvidia). It's safe to ask chatgpt for specifics regarding each. Additionally you can install WizTree to help determine what's eating up all that space.

As well as the above OP, there is a program you can run called Disk Cleanup, if it hasn't been run for a while that can free up quite a few gigabytes of data, these are usually files no longer needed by programs or left over files from installations, the above post is spot on, NVidia leaves a lot of files on your PC after any installation.

I run this program daily, and have done for many years.

There is a lot variance as far as how much space games require. Uninstalling a small game will do little to free up space whereas you will get a lot more space uninstalling a very large one. Do this:

1. Click on Steam at the top left corner, then Settings, and then in the window that appears, Storage (Steam -> Settings -> Storage).
   
2. At the top select the drive that you wish to make space. If you only have one drive then it should default to "Local Drive (C:)".
   
3. The list of games should default to being ordered by "Size on Disk."
   
4. Go through this list and select games that you no longer play by clicking the grey boxes to the right of the shown game size. The games toward the top of the list are larger so your goal is to uninstall those to gain the most space.
   
5. Click "Uninstall" at the bottom.

Note: Some games do not support Steam Cloud and so your progress will be deleted when you uninstall them. There are ways to deal with these games, but for now just uninstall games that you don't mind losing game progress.