Hello Takesari18,
Welcome to the Apple Support Communities.
We understand that you rely on your iPhone alarms to alert you at the right time and we are happy to help you find a solution here.
To start, we would suggest removing and enabling a new alarm to replace your existing alarms. Please test the alarm after this to find out if the alert sound is played as expected: How to set and change alarms on your iPhone - Apple Support
If you continue to notice the same issue, please make sure these settings are configured as follows:
- Settings > Sounds & Haptics > Headphone Safety > Reduce Loud Sounds is disabled.
- Settings > Sounds & Haptics > Change with Buttons is enabled.
- If you have an iPhone that uses Face ID. Open the Settings app, tap Face ID & Passcode, then turn off Attention Aware Features.
If you are unable to find a solution using the information above, please contact Apple Support directly for more help.
We hope that this answer helps.
Cheers!