Downgrade of storage not working

What happens when you downgrade or cancel iCloud+

• If your iCloud storage exceeds your new storage plan capacity, iCloud won't sync or update your information. iCloud updates again when you increase your storage capacity or delete information to make more space. 
• If you downgrade to the free iCloud plan, your storage will be reduced to 5GB and you will no longer have access to iCloud+ features like Hide My Email, Private Relay, and HomeKit Secure Video support.*
• When you downgrade or cancel your plan, the storage change takes effect after your current subscription billing period ends.** 
• To make sure you don't lose any information, learn how to copy what's in iCloud. 

Learn what happens if you sign up for Apple One and downgrade your storage plan.

See >>> Downgrade or cancel your iCloud+ plan - Apple Support