I literally just bought this phone. It has 2 photos and no music. How has it used 44 GB already?
In my storage breakdown the highest thing is apps at 1.2 gb
Open My Files app and browse the Internal Storage folders, you should see there all your phone's files. Look for any folder that may sound that have been created via the Smart Switch transfer you did when moved from iPhone.
It's clearly showing that your System/user data is using that amount of space but it makes no sense as mine, with over 100 apps installed and the OEM plus the rest of other usual files for me are using just 18.9 GB of storage.
I'm afraid that if by browsing your folders and files you don't find the obvious reason of this you will need to do a factory reset, I'd suggest you to at least use the Samsung Cloud backup so you can get back your Home screen and common settings plus any video, pictures and music you may have.