Do not mute Sound on incoming notification - Android, YouTube Is there an option to manage sound notification behaviour on a Android phone?

Description:
In the morning, I do watch YouTube lectures, but every minute or so I do receive Slack message, that mute the voice in the video for 5 seconds. It is really annoying, and hard to listen the lecture.

How it should be:

Option 1: Allow a notification to interrupt the sound/video stream without muting it (so the 'bip' would overlay/merge to the sound stream, but the video would continue).
Option 2: (the current system state): Mute the application, but do not stop the video (very annoying)!
Option 3: Mute the application, but stop the stream/video/music.


I know that there are some option to mute the phone (manual), or install an app (automatic), but I do not wan't do mute the notification itself. I do want to hear it, just without muting the sound/video/music that is currently playing!

My system Android 5, Samsung Galaxy S5

Greetings
Jakub

Related topic:
Disable Notification while watching Videos or Listening Music
The Don't Pause! app promises to help here:


  Are you tired of Notifications interrupting your music?
  […]
  Don't Pause was designed to keep your device from interrupting you when you are listening to music. If you are listening to music through your android phone and you get a text message or email, by default, Android pauses your music and plays the notification. Don't Pause fills in here. Don't Pause will run continuously once you start it and when you are playing music it automatically puts your notifications on vibrate. After you finish your music, Don't Pause automatically changes your setting back to the normal ringer.


I have not tried the app myself (no use-case for me), but a 4-star rating with more than 2.5k votes sounds promising.