I always enjoy a good science and maths podcast, and Up and Atom by Jade Tan-Holmes is, in my opinion, among the best. She engagingly presents a wide array of complex material in a very digestible, understandable form. Recently, she has started doing slightly longer-form videos and they are excellent. Her piece on the Four-Colour Theorem (something that’s very near and dear to my heart) covered not only the mathematics proper, but also some of the history and the philosophy of mathematics and epistemology that the eventual [spoiler alert!] proof affected. Top-notch stuff.
Some of my favourites: