After trying all the hacks and tools (Audacity, audio recorder etc )
Finally found this Open Broadcaster Software (OBS), which is super easy and just does the job.
In Settings → Audio, I was able to select:
. Audio output (Either desktop or earphone or bluetooth also possible)
. Mic - (Desktop | earphone)
For Source, I selected Screen Capture (XSHM) to capture the entire desktop or can keep it blank as well.
To install:
sudo add-apt-repository ppa:obsproject/obs-studio && sudo apt install obs-studio