It's a great question to find some hidden gems!
Personally, I prefer taking courses on edX.
In my opinion, it is one of the best online sources of learning out there, speaking from experience.
Many prestigious and well-known institutes such as MIT, Harvard, Berkeley, etc. worked and keep working collectively to provide high-quality material (lectures, labs, assignments) with each course having an exceptional community which will be present at all times to guide you and answer your questions.
Also, there are many inspiring stories of learners from around the world, who have spent time taking courses on edX.
Whatever platform or class you take, just remember that you get out of it only what you put in. You cannot learn by observing - you need to jump in and engage deeply with the content. Enjoy!
Don't miss my new newsletter issue on Monday, get it first here