Hard Drive Space for Monterey install

Rebuild the Spotlight index on your Mac

By virtue of the failed Installation of Monterey and the error message presented - this kind of confirms the required Empty Space is not met.

What is “Other” storage on a Mac, and how can I clean it out?

Free up storage space on your Mac

OmniDiskSweeper Safe to use

How to delete Time Machine snapshots on your Mac

See used and available storage space on your Mac

The final word from Apple on Managing the " Other " Category

• 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.

The is possible a misunderstanding of what iCloud Does and Does Not do.

Firstly - iCloud was not designed or intended to be like an External Drive to be used to archive or store files ignorer to create space on the Internal Drive.

iCloud was designed to have file, of may sorts, available on the iCloud Drive so changes made on one device is available and reflects on all other drives signed into and using the same Apple ID.

As previous posting indicated, copies of all the files located on iCloud Drive are also on the Internal Drive. That is so when Internet Connect is not available and a change to a file is made - when Internet Connect is re-established, those changes are then uploaded to iCloud.

So the issue, in this case , needs to move some of the large files off the Internal Drive to achieve the desired results.

By default iCloud drive stores all your files and full-size photos on both your device and in iCloud. If you go to About this Mac>Storage>Manage and click on Store on iCloud it stores all files in iCloud but on photo thumbnails and recent files are stored on the device. You can access all your files and fill-size photos through iCloud.