I have other creative pursuits but started drawing in my 50's and it's more fun the more I do it. When I started I tried a Udemy drawing course (from a work account) and it wasn't very helpful, then same as you I found some Proko videos on YouTube and they were awesome. I love the range of things you find in the Drawing Basics course, now I'm hooked. Steven Michael Hampton's courses have been very helpful to me as well, especially head construction and gesture. I also tried some other art learning sites and came back - I think Proko is doing things better. The information is deep (a lot of courses out there stay too basic) but it also isn't pedantic, or overly transactional trying to monetize every little interaction on the site (other common problems I found). It's great that you can keep revisiting your course forever unlike subscription sites. I think the way representative student critiques are part of the series is brilliant, most of the time it covers common mistakes you might have made.

Really I think it was the Draftsmen pod casts. I've drawn off and on throughout my life. I received encouragement, but little formal training. Some art classes K-12, some drafting in college (At one time I had aspirations of becoming an engineer). A few years ago I got a little more serious, bought some books, started watching youtube videos, but mostly I just kept doodling. About a year ago I stumbled onto the Draftsmen podcasts and started binging them. It changed the way I looked at (picked) videos and how to learn. By last summer, I decided to get more serious, so I signed up for a drawing class at the local college, and the Drawing Basics here. Both have been really helpful. As I'm actually seeing some improvement, and fairly quickly compared to past attempts it has also increased my motivation, which leads to more actual pencil to paper time.