Do you still have the retail box it came in which would show the specs of the phone.
Nothing you can do would change the actual storage capacity of the phone.
Perhaps you were mistaken when you first looked.
One can get excited when first unboxing a phone to get the phone set up etc.
The capacity will be as shown in Settings.
You can clear up storage taken by deleting items from the phone and move photo's and videos etc to any relevant Sd card.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.The advice I offer is my own and does not represent Samsung’s position. I'm here to help. " This is the way. "