Cannot clean my iCloud

Try going to iCloud.com/iCloud Drive using a computer browser to see if you see any documents there. Then click on Recently Deleted at the bottom right. If there are files there you do not need, delete them. Then try iCloud.com/Settings and go to Advanced at the bottom left. Access Restore Files. If there are files there you do not need, delete them.

The maximum storage occupied as shown in your screen shot is for documents and photos , if you had set up iCloud Drive ( checked the box of iCloud Drive in system preferences > iCloud , click on option button the desktops and documents box is checked see these articles https://support.apple.com/en-in/HT204025

https://support.apple.com/en-us/HT206985

https://support.apple.com/kb/PH27919?locale=en_US&viewlocale=en_US

https://support.apple.com/kb/PH12790?locale=en_US

Remove unnecessary back ups if the back is completed , photos / videos , what's app messages .

See what storage space is designated , if you exceed the limit , remove the data or upgrade to new iCloud storage ( purchase storage from apple see this article https://support.apple.com/en-in/HT201318

https://support.apple.com/en-in/HT201238

and if you are not interested to purchase the iCloud storage reduce the data using optimise feature and deleting unnecessary data https://support.apple.com/en-gb/guide/system-information/sysp4ee93ca4/mac

Regarding the space for other documents as shown in your question as 91.5 GB this might be reduced by apple care senior advisors ( refresh the account ) see this link https://support.apple.com/en-in/HT201232