My use-case is simple: start a playlist with audiobooks and slowly fade out volume within 20-30 minutes to help my kiddo fall asleep, I tried a number of "alarms" and "timers" apps, and all of them fade volume only upon timer expiry, i.e. within last 10-15 seconds, not acceptable.
Some apps designed solely for this purpose are not in the AppStore anymore, e.g. http://fade-sleep-dream.appstor.io/
I can't believe such simple and actually useful feature is not available on a smartphone...
Any advice is greatly appreciated.