iphone storage doubled??

Hi so I recently replaced my iPhone 11 with another iPhone 11 because the display was messed up. Both phones have 64 GB of space, and on my old phone it said i had only used about 30 GB. Once I transferred all my data to my new phone, however, it says my storage is full at 63.8/64 GB. I thought it might be because I know had two versions of essentially the same phone both taking up storage, so on my old phone I went to my settings and hit the ‘erase all content and settings’ button to factory reset it but it still shows my storage as full. Does anyone know why this might have happened? It’s really irritating because half of my apps are now stuck in limbo loading when I know for a fact that I checked before purchasing the new phone and my storage was at 30/64 ish.