It's a highly informative video and you do great work posting this stuff, but I'm slightly aghast that Max Planck's name didn't come up (at least to the point I watched) when it was delving into a topic such as quantum mechanics.
The door which opened Quantum Theory itself was the result of Max Planck's 1900/01 paper "Ueber das Gesetz der Energieverteilung im Normalspektrum" (On the Law of Distribution of Energy in the Normal Spectrum). With no intentions of becoming a scientific revolutionary, he was working on a solution for blackbody radiation and found that the energy of a vibrating molecule could only take on certain values and that it would have to be proportional to the frequency of vibration, which led him to postulate that light energy could only be emitted and absorbed in discrete packets he dubbed "quanta".
how much they knew in the 20s
Indeed.
The vast majority of today's (physical) science is built on and a direct result of the work done in the first half of the 20th Century, particularly the first quarter of it. There has been no sort of paradigm shift which completely flipped our understanding of reality on its head on that kind of level since, General Relativity and Quantum Mechanics are the two pillars which encompass modern physics.
this is "cac science" breh
It's absolutely disgraceful and beyond embarrassing some people actually do think this way. Few things could possibly be more self-defeating, I won't bother getting into the many reasons why in this post but I will say that STEM literacy and anti-science attitudes are getting to be at desperate levels in the USA and it completely transcends race, it's a massive problem with potentially disastrous consequences for the future and one that needs to be reversed quick fast.