my iphone won't take incoming calls but texts arrive fine

same thing happened to mine after I set up a Sleep focus on the Watch, it was syncing the quiet hours to the phone. Settings > Focus, open each one, check the schedule and the Share Across Devices toggle. then Settings > Phone > Silence Unknown Callers. if both are clean do a Reset Network Settings and if that fails ring the carrier and ask them to clear call forwarding on your line, that's set on their side and survives everything you do on the phone.