I'm using Mojave and not Big Sur. I offer the following suggestion that -might- work with Big Sur.
I regularly clean out my user library caches -- wipe them out.
What you need to do:
- Quit all open apps except for the finder
- In your user account, open the "Library" folder*
- Locate and open the "Caches" folder
- Hit "command-A" to select all items in that folder.
- Drag them to the trash (I have the trash can icon in the tool bar in my finder windows, I just select all and click that).
- Empty the trash.
* You may need to be "in the finder", then go to the "go" menu, and choose "Library" to get to the user library.
The cache files will automatically be re-created by the apps and processes that use them.
If you use Safari, there's another way to quickly empty the Safari caches:
- Open Safari preferences
- Click the "advanced" tab
- Put a check in "show develop menu in menu bar"
- Close Safari preferences.
Now, when you want to dump the cache in Safari, just go to the Develop menu and choose "Empty Caches".
I went to the "Keyboard" panel in system preferences, and created an application specific key command for Safari to do this (I chose "command-E").
Now I just hit command-E and the caches are cleaned.