I have managed to reroute audio from one channel to another on Android, and using only Tasker. Therefore, it will no longer be necessary to use the well-known SoundAbout app, at least with the most common audio channel: Multimedia.
These are the available routings:
• Headphones > Speaker (and viceversa)
• Headphones > Bluetooth (and viceversa)
• Speaker > Bluetooth (and viceversa)
- The values and the way how the task manages the audio routing were based on my current device and ROM. So, it could work or not for your device.