iPhone 13 Pro Max not ringing for incoming calls

Since restoring from backup to a new iPhone 13, I am missing calls left and right because my iPhone doesn't "ring" (also, alarms and other audio notifications don't work -- even though I have checked to make sure the "ringer" is on and at full volume (the iPhone does VIBRATE -- but that's not enough for me to know a call is coming in if I am otherwise occupied). I (think I) disabled "focus" and "do not disturb," but somehow or other, the phone keeps reverting back to some form of "silent mode." What am I missing?