I teach IT courses (mainly Linux System administration I and II) in classroom and webinars. I have also taken some programming courses and I'm still taking language courses.

I would say that intro courses starting from scratch are still good, especially if you're a busy guy. You may know the basics but you probably have holes in them. On the other hand if you have basics covered you can go to advanced (level 2) course.

My experience is also that if you don't use the knowledge on some project (can be hobby or self learning) in a year after taking a course you will have forgotten most of it, while the stuff you used extensively even a decade ago can be recalled very quickly.

You could find individual weekly course where you also get homework - can probably be found online. You could work it out with someone remotely.