You're right. PBS Digital Studios has a fantastic Youtube presence. One of my favorite YT channels is PBS Spacetime, which gives a somewhat mathmatically rigorous treatment on cosmology/astrophysics. It's so much better than anything on the Science or Discovery channel. I learned about the coolest phenomenon ever: a KugelBlitz (a hypothetical type of black hole formed from light), overtaking quasars as my fave astronomical curiosity.

They also have PBS Infinite which is a maths series. I learned what a random walk is today.

I urge any and every one to check out their various Youtube channels. It truly is a travesty that we have extra money to spend on the F-35 and other overpriced, unnecessary military expenditures, but the pittance we give to PBS is being cut.