iPhone 14 sound not working unless on speaker

Just to confirm, when you're not using speaker mode, you're holding the iPhone to your ear, right? The earpiece is designed to work that way, so you won't hear sound unless the phone is near your ear. If you're using speaker mode, the sound should play freely.

Otherwise, please review this support article:

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

Put the tip of the iPhone against your ear and listen. On Face Time, it automatically makes the audio come out from where the front cameras are for privacy. Speaker makes the audio come from the loud speakers on the bottom of the iPhone.

Best Of Luck!