macOS Catalina and later
“macOS Catalina runs on a dedicated, read-only system volume called Macintosh HD. This volume is
completely separate from all other data to help prevent the accidental overwriting of critical operating system files.
Your files and data are stored in another volume named Macintosh HD - Data.
In the Finder, both volumes appear as Macintosh HD.”
Storage
A user has no control over “Other” category of storage.
Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.
https://support.apple.com/guide/system-information/see-available-storage-space-syspf9b375b9/11.0/mac/11
What a user can do?
1. Delete files
https://support.apple.com/guide/system-information/find-and-delete-files-syspf5a64aa6/11.0/mac/11.0
2. Optimize storage
Click the “Manage”button. Wait until Green “Completed” button appears.
https://support.apple.com/guide/system-information/optimize-storage-space-sysp4ee93ca4/11.0/mac/11.0
3. How to free up storage space on your Mac
Try all other steps posted in this article
https://support.apple.com/en-us/HT206996