I did not find any documentation about a more accurate compass data by mobile net from Apple. This is my personal testing experience and it seems to be true for all devices I tried(iPhone Pro 12, 14, 15, iOS 17+). Using a simcard results in my case to more accurate heading (maybe celltowers make the difference).
JohnnyBanana
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Post
Replies
Boosts
Views
Activity
Apple fixed this issue with iOS 17 beta 2, works again.