Faint iPhone 13 alert tones cannot be fixed

On my iPhone 13 Pro (iOS 16.4), under Settings\Sounds &Haptics\Sounds and Haptic Patterns, only “Ringtone” responds to my  preferred “alert volume” and “change with buttons” settings. All others (text tone, new voicemail, sent mail, calendar alerts, and reminder alerts) can barely be heard… they all  sound at useless, nearly inaudible levels, even if I set the “Ring tone and alert volume” slider all the way to maximum.

This problem continues even after I have done a Settings\General\Reset\Reset All Settings, and even persists after I have done a backup to iTunes followed by a total iPhone erase\restore. Also, turning off facial attention features, doesn’t work either.

What am I missing, and how can I fix this problem?