Hello lalucere,
We want to start off by making sure we provide the steps in this article: How to set and change alarms on your iPhone. These simple steps can adjust the alarm volume:
"How to change the alarm's volume
- Go to Settings > Sounds & Haptics.
- Under Ringtone and Alert Volume, drag the slider left or right to set the volume. As you drag, an alert will play, so you can hear how the volume changes.
- Turn on Change with Buttons to use the volume buttons on your device to change the alarm volume."
The article also offers the following troubleshooting for low alarm volume:
"If the alarm volume is too low or quiet
Do Not Disturb and the Ring/Silent switch don't affect the alarm sound. If you set your Ring/Silent switch to Silent or turn on Do Not Disturb, the alarm still sounds.
If you have an alarm that doesn't sound or is too quiet, or if your iPhone only vibrates, check the following:
- Set the volume on your iPhone. If your alarm volume is too low or too loud, press the volume button up or down to adjust it. You can also go to Settings > Sounds & Haptics and drag the slider under Ringtone and Alert Volume.
- If your alarm only vibrates, make sure that your alarm sound isn't set to None. Open the Clock app, tap the Alarm tab, then tap Edit. Tap the alarm, then tap Sound and choose a Sound.
- If you connect headphones to your iPhone, the alarm plays at a set volume through the built-in speakers on your iPhone as well as wired and wireless headphones.
Manually adjusting the time on your iPhone in Settings to change app behavior, like game timers, isn't recommended and can affect alarms."
If the issue persists, further assistance may be needed. We want to make sure you reach the right team for help with your device, so we recommend that you contact Apple Support directly. Depending on your region, you may be able to reach them here: Get Support.
Thank you for participating in the Apple Support Communities and have a wonderful day.