Is there any way to see what's being stored and free up space?

That's strange.

1. Is your iPhone running the latest iOS version (now 13.7)? Shouldn't be this case, I suggest that you update it, then test your storage again.
2. What happens if you force restart your device, using these instructions?:--> Force restart iPhone – Apple Support Did your storage change?
3. What do you see going to Settings>General>About>Available GB?
4. Do you have a computer running iTunes (PC) or iTunes/Finder (Mac)? If yes, what is your iPhone's storage shown there?

Regards

Giulio

Thanks for your answers.

Something could have gone wrong during the latest update, so my last attempt is as follows:

Create a full backup of your device, then restore it to factory settings, performing this procedure and, in the end, set your iPhone up as new:--> Restore your iPhone, iPad, or iPod to factory settings – Apple Support

When done, restore data from your previously made backup:--> Restore your iPhone, iPad, or iPod touch from a backup

Check your storage again. If the issue persists, contact Apple Support using this link:--> Get Support

They will be able to help you about that weird "other" / "on my iPhone" storage.

And please, let me know how it goes, thanks.

Regards

Giulio

There could be many places where, data could have been stored on "On My iPhone" - such as Calendars, Notes, Files App etc..

Watch the GIF below

Glad you could work it out. No, sorry, no idea about your glitch, I've never seen nor experienced similar behaviors.

Which iPhone model are you using?

Excluding the latest procedures you performed yesterday or today, have you recently restored your device? If yes, how did you restore it?

Giulio

Just talked to another senior member of our Community. Neither he nor I know / have used that application, so we can't make judgments, but we suspect it may have been a glitch coming from right there. I don't want to blame anyone, but I would be careful in the future to use that program (at least you need to be sure that this application is updated to be able to use it (compatible) with the latest iOS version).

Not even my colleague has ever seen a situation comparable to yours (so much space occupied "on my iPhone", for no apparent reason).

Have a good day and ... stay safe.

Giulio

Giulio

:)