A few things...
- make time setting more user friendly
- don’t stop the timer when phone is shut off
If these were added I’d give it a 5/5.

Archived App
This is an archived listing of the app previously available on the App Store.This utility app allows you to set a timer to automatically stop your music. Simply start your music in any app, set the desired duration in this app, and it will fade out your audio when the time is up. It also dims your device's screen to a minimum brightness.
1.0
May 25, 2019
You start your music in any app, then open Sleep Music Stop - Timer to set a countdown. When the timer finishes, the app automatically stops the music playback and dims your device's screen to minimum brightness.
The provided data does not specify if Sleep Music Stop - Timer contains advertisements. It is listed as free with no in-app purchases.
Sleep Music Stop - Timer is compatible with iPhone, iPad, and iPod devices.
Sleep Music Stop - Timer has an age rating of 4+, making it suitable for younger users and adults.
Sleep Music Stop - Timer was last updated on May 25, 2019, with version 1.0.
Sleep Music Stop - Timer has a user rating of 2.0 stars based on 2 ratings.
Yes, the app is designed to work with any music application you choose to play your favorite music from.
Yes, the instructions indicate that you should not exit the Sleep Music Stop - Timer app for the timer to function correctly and stop the music.