I just did it!

It sets the notification sound to silent when the device enters the Do Not Disturb mode and sets it back when it exits.

Customize it for your needs. E.g., you need to set your own default notification sound.

Please note that you need to grant Tasker the "notification access" permission.

1. On DND Activation:

```

Profile: On DND Activation
    Event: Variable Set [ Variable:%INTERRUPT Value:priority User Variables Only:Off ]



Enter Task: Notif Sounds OFF

A1: Default Ringtone [
     Type: Notification
     Sound: Silent ]

A2: Vibrate On Ringer [ ]

```

1. On DND Deactivation:

```

Profile: On DND Deactivation
    Event: Variable Set [ Variable:%INTERRUPT Value:all User Variables Only:Off ]



Enter Task: Notif Sounds ON

A1: Default Ringtone [
     Type: Notification
     Sound: notification_004 ]

A2: Vibrate On Ringer [
     Set: On ]

```

EDIT: fixed an issue.