Apple could not figure out what the problem with the iPhone was so they sent it back to be. Now it will be a few hours to set the phone up for use again. The battery still shows 100% capacity suggesting the service life may be slightly better than the iPhone 7 that has seen better days.
Had some problems getting music to sync but after a few attempts it is working. The playlists occupy less than 50% of the 256 GB of the phone capacity so it is not a problem for at least a while.
WiFi is still slow compared to the iPad so its not clear what is wrong. LTE is even slower.