Storage

When you get a popup message on your iPhone or iPad that the storage is full.

Look closely into the storage of the iPhone and iCloud.

iCloud storage is primarily for keeping a copy of your iPhone data safely on the cloud. If you delete data on iPhone, data on iCloud is gone too.

Turn iCloud features on or off

1. On your iPhone, iPad or iPod touch, go to Settings > [your name] > iCloud.
2. Turn iCloud features on or off.

Turn iCloud features on or off - Apple Support

iPhone Storage (Setting > General > iPhone Storage)

1. Total storage remains the same throughout the lifespan of the iPhone
2. Storage can not be enhanced
3. You may take back up on Mac or PC using iTunes without iCloud

iCloud Storage (Settings > [Tap your name] > iCloud)

1. By default, every user gets 5GB of free storage space
2. You can buy more storage based on your requirement of 50, 200GB, and 2TB with a monthly subscription
3. Based on your storage capacity you can back up your iPhone or iPad
4. Space can be shared between your family members for a storage plan beyond 200GB

Following up on what SravanKra says, since your iPhone 14 Plus has 47.8 GB of local storage free (out of a total of 128 GB), and is complaining when you try to take a photo, I would surmise that

• You have iCloud Photos turned on, and
• You have run out of storage space in iCloud

When you use iCloud Photos, it keeps full-size copies of all of the photos, from all connected devices, in iCloud. If you are out of iCloud space – because you never signed up for anything other than the free 5 GB, or because your data has filled up a higher-capacity plan – then I'd expect the iPhone to start complaining in one way or another.

Manage your photo and video storage - Apple Support