Well said dude if you can't understand what the teacher is teaching that means the teacher is bad,
And here we are with David Malan one of the famous CS teacher, well you can say that he's an amazing teacher just by how energetically he teaches and how excited he is to teach everyone who wants to learn.

Well the Harvard CS50 introduction to computer science and course like other are actually pre-made thoroughly by lots of teachers before they are taught by David Malan, you can see who and were involved in tidying up the course as he introduces them to you at the beginning of the course.

Ok, so my last point, as you said he is the best of the best teacher that's not really how it is, yeah everyone has their own way of learning, but you will find lots of useful people online who wants to share their knowledge on a specific concept, a quick YouTube search on a topic will give you vast array of amazing tutorials and then you choose which best suits you.

Also there are professional courses online here and there very well made like the courses offered by Udacity and edX made by industry experts like Google, Apple, Amazon etc. And there are also amazing websites like Khan academy udemy etc.
All of these provide wide range of amazing complete tutorials and education on specific concepts.

Let me know if you need any help in find any thing else like determining which courses which will be the best for the learning experience.

Warn Regards
@asteemian