Alarm clock volume?

Set the alarm's volume

Go to Settings > Sounds & Haptics. Under Ringers And Alerts, 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. If the alarm volume is too low or quiet, learn what to do.

How to set and manage alarms on your iPhone

1. Open the Clock app, then tap the Alarm tab.
2. Tap .
3. Set a time for the alarm. You can also choose one of these options: Repeat: Tap to set up a reoccurring alarm. Label: Tap to name your alarm. Sound: Tap to pick a sound that plays when the alarm sounds. ... 
4. Tap Save.

How to set and manage alarms on your iPhone - Apple Support

You may use any song and convert to a Ring Tone and use it as Alarm

To convert any song into a Ring Tone read below

Do you have GarageBand?

Here you have the process!

My GarageBand opens my iCloud Drive. In your case it may not be so. Nevertheless the process remains the same. This helps because accidentally if you open up the iCloud Drive using GarageBand you can get back to GarageBand.

Music bust be on your iPhone not on iCloud Library.

When you select the song Hold and tap the Song delicately for it to populate it in Audio Recorder.

Watch the GIF below to convert any music to RingTone

This is made on iOS 13.3.1 iPhone SE

And then use my previous post to see how to use Ring Tone as an Alarm

Watch the GIF below