I suggest split into smaller modules for better follow up of the topics.
Also to improve sound quality.

its really good material but its too hard to understand the professional doing the talk because he is not native speaker and he is too far from the microphone.

How hard is it to use a decent microfone?
And if this talk happened to be recorden without one, how hard is it to do it again?

This content deserves better audio quality.

Useful, but with very bad sound: doors shutting, prople coughing...