An old mobile phone makes the perfect bedside clock, music and audiobook player.

Ideally, the phone has an amoled display and an audio jack, but Bluetooth works as well.

Settings / apps suggestions:
https://www.reddit.com/r/androidapps/comments/6wdr3s/tip_send_alarm_sound_only_via_connected/
Sleep on Android or Earphone alarm to send the alarm through the earphone or bt speakers instead of the phone loudspeaker.

https://play.google.com/store/apps/details?id=ak.alizandro.smartaudiobookplayer

Smart Audiobook player or Audiobookshelf for own audiobooks.

https://play.google.com/store/apps/details?id=com.maxmpz.audioplayer
Poweramp music player or any other player of your choice.

Rotate screen or even different launcher like Nova - to rotate the homescreen to landscape.

Google clock - for option to display clock as screensaver and dim during night.

Disable screen lock. Remove/disable all other apps. Set google play pin to prevent accidental or unauthorised purchases.
Set always on while charging? Dev options
Remove phone/messaging/camera from quick launcher
Adjust homescreen grid to 5×8 for better center placement of music+audiobook app. Add widgets if preferred or available.

https://play.google.com/store/apps/details?id=com.phascinate.precisevolume
Precise Volume app for volume fine control. Licensed version allows for per app volume settings helping different volume levels between music/audiobooks.

3D print stand ideas
1. https://www.thingiverse.com/
2. https://www.thingiverse.com/thing:4929701
3. https://www.thingiverse.com/thing:4929496
4. https://www.thingiverse.com/
5. https://www.thingiverse.com/thing:5062324
6. https://www.thingiverse.com/thing:5083891/comments
7. https://www.thingiverse.com/thing:4626956/makes

1. https://www.thingiverse.com/thing:3577183
2. https://www.thingiverse.com/thing:2592505
3. https://www.thingiverse.com/thing:2319783
4. https://www.thingiverse.com/thing:3936479