Same problem.
Got my iphone 14 pro max yesterday.
Went through setup process, including update of iOS to 16.0.2
transfered my iphone 12 pro max to my new 14 pro max via iCloud restore
Logged in all the apps
Went to sleep with “79 GB of 256 GB Used”
Woke up this morning:
System data ballooned over night to “195 GB of 256 Used”
The same issue has happened to my wife one year ago when she bought a new iphone 13 pro max. System data grew massively during that first night after the transfer from the older iphone. Massive surprise for her in the morning. Now the same thing has happened to me. #storageanxiety