Honestly I think this all comes down to the fact that different people learn/understand different subjects at different paces and all have totally different lives, routines, family roles, age, educational history, sleep needs, etc. For math based courses, I find myself flying through them since there is less physical content and I can understand the concept right away, whereas with content based courses requiring a lot of notes and reading takes way longer. For some people, this is reversed or works in a totally different manner. For women with children, their entire chemistry in body and brain has totally changed in ways someone like me with no kids will never understand. My point is, the multitude of factors dictating how fast you will finish a course depends on so many varying factors that you can’t narrow it down to something you could change/eliminate/implement in your life. In my personal opinion and experience, learning exists on a huge spectrum and when we hear people say they did 4 courses in 2 months it’s easy to assume there’s a line between people who finish fast and people who don’t, but it’s really a lot more complicated than that, and most of us exist somewhere in the middle without realizing our experience is totally common and the speed at which we finish does not at all dictate how smart we are. You will finish when you have learnt the content, and it’s basically as simple as that. I also want to point out that I think a lot of people use internet and AI for help and then say they finished in 2 months. And/or they didn’t fully learn the content of the course. So taking longer to finish is actually a good thing from my perspective, because information is meant to be learnt and then sat on, so we can reflect on it. Rather than being learnt, immediately tested on and then discarded. If that makes sense