My iPhone says memory full but I have upgraded iCloud for more storage

If you have upgraded iCloud storage and are seeing a message on your device that storage is full then it is possible you are not making the best use of iCloud storage and need to use optimization features. If you do have optimization activated then it is possible you are exceeding your device's needs in terms of on-device storage and you need to buy a device with more storage.

Click on the link to learn how to optimize the storage on a device --> "How to check the storage on your iPhone, iPad, and iPod touch" - How to check the storage on your iPhone and iPad - Apple Support

- "If your device is low on storage, it automatically frees up space while installing an app, updating iOS or iPadOS, downloading music, recording videos, and more.

To make more storage available, your device can remove some of your items, like streamed music and videos, files in iCloud Drive, and parts of apps that aren't needed. It also removes temporary files and clears the cache on your device. But your device only removes items that can be downloaded again or that aren't needed anymore."

Here's the same information as a video: "How to free up space on your iPhone, iPad, or iPod" - https://youtu.be/bnhuHSv_WrI

Optimization specifically with reference to "Set up and use iCloud Photos" - Set up and use iCloud Photos - Apple Support

--> Save space on your device

iCloud Photos keeps all your photos and videos in their original, high-resolution version. You can save space on your device when you turn on Optimize Storage.

Manage your photo and video storage - "Learn how photos and videos use your iPhone, iPad, and iPod touch storage, ways to save space, and how to upgrade your iCloud storage if you’re running out."

Manage your photo and video storage - Apple Support

Another way to free storage on a device is to transfer items to a computer and move them to locations which are not part of iCloud so they won't just sync back again. The items are archived on the computer and on backups you make of the computer. Read this article to learn how to sync your iPhone, iPad, or iPod using your computer - Sync your iPhone, iPad, or iPod using your computer - Apple Support