This is a software issue. What I suggest is backing up your iPhone with iCloud backup (Settings -> Your Name -> iCloud -> iCloud Backup -> Backup Now - Unless it has already recently backed up), then make sure you get your wifi password and Apple ID password.

***If your Apple account sends you verification codes all of the time you need to add another number to your account in Settings -> Your name (or iCloud) -> Password & Security -> Edit to add trusted phone number (you wont be able to get the code when you sign back in)>.

After you've backed up. Sign out of iCloud, erase the iPhone (Settings -> General -> Reset -> Erase all Content And Settings) and then set up the phone, but restore from the iCloud backup. You'll need wifi, Apple ID account login (and a verification code from another trusted number if your account sends you verification codes). Once thats done the phone will look the same, messages, apps, photos, notes, calendar events, etc.