Problems after update to ios 15

If you have a hearing or sound issue on your device then please try some of these processes to set it right

1. If you have a distorted sound issue on your iPhone --> If you hear no sound or distorted sound from your iPhone, iPad
2. If you are not able to hear the other person, click this...>If you can't hear a person on a call or voicemail or if the sound isn't ...
3. If you only hear through speakerphone mode --> If your iPhone is stuck in headphone mode - Apple Support
4. If the other person is not able to listen to you then please click this to identify the issue --> If the microphones on your iPhone, iPad, and iPod touch aren't ...

If the above options do not mitigate the issues then Contact your carrier and then Contact Apple Support

I believe i have the same issue that you do.. The volume, whether it be an alert/notification/ringtone/alarm/caller on phone, is just extremely low. When I attempt to turn the volume up from regular OR silent mode, it always thinks I’m in silent mode & briefly displays the message, “Silent mode off.” However, it never really gets out of silent mode, as it seems to reset itself back into silent mode upon toggling the sound/silent switch. I’ve tried everything that I can possibly think of - dragging the volume slider back & forth, toggling “change with buttons,” deleting/re-adding alarms, reset settings, soft reset, hard reset, toggling airplane mode on/off, pressing volume up while on a live call, resetting AirPods Pro settings, regrettably to no avail… I’m out of ideas & can’t afford to sleep through my alarm one more day.. 😬 I should also mention that my iPhone (iPhone XS) started doing this immediately after I updated to iOS 15. I’m kicking myself now, as I had the option to choose between iOS 14.8 & iOS 15… I’m not gonna lie, I was super stoked about being able to store my Covid-19 vaccination record in the Health App.. yup, I chose iOS for that.. 🤷🏼‍♀️