Downgrade iCloud
Cannot downgrade iCloud on my iPhone
iPhone 13 Pro Max, iOS 16
Cannot downgrade iCloud on my iPhone
iPhone 13 Pro Max, iOS 16
Did you follow the steps mentioned in this article to do so?
Downgrade or cancel your iCloud+ plan - Apple Support
Also check this requirement:
...
Before you downgrade or cancel your iCloud+ plan, first download or remove content that exceeds your new storage amount. To make sure that you don't lose any information, learn how to copy what you store in iCloud.
...
copied from: Downgrade or cancel your iCloud+ plan - Apple Support
If you previously clicked it successfully, wait until the current billing cycle ends. Otherwise, see the section about that issue in the article Ingo2711 linked to.
(231985)
I already deleted the exceeding files. Just only the finish button is grey, cannot finish the downgrade.
Downgrade iCloud