Back when my wife had this issue, I tried everything and anything you can possibly do to make it work. I found out it worked when I removed the SIM card, before resetting the phone, then it would go back to the same broken phone eventually.
Long story short, Apple said it wasn’t not their fault, but told me this issue was anticipated by their engineers but there was nothing they can do?? So we had to purchase a new phone and I’m sure that was apart of their plan all along to force a new buy.
Good luck!