Should I do offline courses or online?

Teaching is a sum total of how much the person knows and how much they can impart. It is always the sweet spot between these two. In the offline world, professors know a lot, but not everyone is great at teaching. In the online world, the trend is reverse. There are people who are great at teaching, great with charisma and communication and storytelling, but their actual knowledge might be relatively low. Neither is bad. There is a need for every kind of course. If you are at an absolute beginner level, optimize for someone who is great at teaching. But as you grow, your needs change. You might be focusing on something deeper. You are okay if it is not the most interesting thing in the world.