App notification sounds are low and cannot be changed!
iOS 17 became available for download on September 18 for supported iPhone models. Some changes in iOS 17 were not welcomed by users; Like new app sounds.
Many users expressed that the new sound, which Apple called rebound from the social media platform, was too quiet. While three tones create relatively high levels of ringing, Rebound sounds like a much quieter version with reverb. When the phone is in a pocket or bag, this sound is more difficult to hear than the three-tone one. Users say that they miss incoming notifications for this reason. Vibration feedback is also weaker and harder to feel.
Apple does not currently offer a way to choose a different notification alert sound for apps or change the volume. In the Settings – Sounds section, ringtone, tone and alert sound can be selected for system applications such as e-mail and calendar alerts. However, these options are limited to Apple’s own apps.