I think you’re going to need to do a full erase and reinstall.

It’s annoying, but far less of a drama than it used to be.

As long as you had iMessages on in iCloud then there’s unlikely to be anything of note that you will lose by starting afresh.

But just think about any apps that don’t have a cloud sync (be that iCloud or their own sync engine). That’s what you’ll lose if you delete.

You’ll need to reset up email accounts etc