The photos take up more memory than they are

You may try some of these steps, please chack after each step....

1. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
2. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
3. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If none of the above steps resolve the issue, it is recommended to reach out to Apple Support or visit an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.

If nothing helped...

Get a Genius Bar Reservation and Apple Support Options - Apple

Contact Genius Bar.

Manage Reservations - My Reservations - Apple

It looks as if the OP has a huge iCloud Photos library (377.27 GB) – one that's so big that it's impossible for the iPhone to store full-size local copies of all of the photos. (The iPhone has 256 GB of storage, total.)

There's a setting on the iPhone that gives it permission to get rid of full-size local copies of photos, substituting thumbnails (or something like that), when it is running out of space. The theory is that since iCloud has full-size originals, one can re-download full-size copies on demand, as needed.

I'm guessing that the OP has given his phone permission to optimize local storage in this way. Maybe the phone has been playing it too close to the limit in trying to fit as much as possible of the 377.27 GB of photos into local phone storage? So that it's always at the verge of running out of space?

Or maybe I'm misinterpreting this and there is something else wrong…