> Rarely(never?) have I found new knowledge on youtube, however its a great source of joy/emotions/slop.

I suspect you are not looking very hard. I have learned a tremendous amount about everything from stone cutting to metalworking to welding to Kalman filters to linear algebra. There is a lot out there. The main annoyance I have is keeping AI slop out of my feed so that I can instead learn from genuine experts. There is a huge amount out there.

Appending 'before:2024' to your search term works on YouTube and gives results from the pre-slopocine era.