I agree that most videos in YouTube simplify the problem too much or are just wrong. My recommendations anyway:
* Mathologer: "Ramanujan: Making sense of 1+2+3+... = -1/12 and Co." https://www.youtube.com/watch?v=jcKRGpMiVTw
* Vsauce: "The Banach–Tarski Paradox" https://www.youtube.com/watch?v=s86-Z-CbaHA
Each one is like half an hour long, but you may need to pause them and rewatch them a few times to understand the details.