iCloud.com storage space

See the article https://support.apple.com/guide/icloud/what-is-icloud-storage-mm7983cbca2a/1.0/icloud/1.0

https://support.apple.com/guide/icloud/check-your-storage-usage-mm6e5a441fc7/icloud

The back ups are also not included https://support.apple.com/guide/icloud/what-is-ihttps://support.apple.com/en-us/HT207428

• Contents of an iCloud backup: Your iOS and iPadOS device backups only include data and settings stored on that device and not content stored in iCloud. See the Apple Support article What does iCloud back up?

Sync applications like notes , calendars , mails , photos .... with iCloud to consume rest of space https://support.apple.com/en-sa/guide/icloud/mmb1de40d9/icloud

Read https://support.apple.com/guide/icloud/what-is-icloud-mm74e822f6de/icloud

You right clicked on iCloud Drive in finder and use get info https://support.apple.com/en-in/guide/mac-help/mchlp1774/10.14/mac/10.14

It will show the iCloud Drive data in which files / folders / your personal documents are saved as you have turned on iCloud drive https://support.apple.com/en-us/HT204025

And desktops and documents box is checked https://support.apple.com/en-in/guide/mac-help/mchle5a61431/10.14/mac/10.14

And the iCloud Drive storage is less ( as you never dumped up massive documents / folders in it ) and it is working normal as the storage is in limits and for the disk space see the article https://support.apple.com/en-in/HT206996