Sorry for being unclear about that.
Did you check the graph on your iPhone, to see what exactly is using the storage space in iCloud?
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Check your iCloud storage on your iPhone, iPad, or iPod touch
- On your iPhone, iPad, or iPod touch, go to Settings > [your name] > iCloud.
- The bar graph shows your overall storage usage.
- Tap Manage Storage for more details.
- Below the graph, you see a list of apps and features and how much iCloud storage they use. The apps and features that use the most storage are at the top of the list. You can tap an app or feature for more information.
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copied from: Check your iCloud storage online or on any device - Apple Support