The video I mean is actually really old. They aired it after 9/11 as proof it was Osama, but some German Muslims saw it an recognised it (besides being able to understand what Osama is saying). It was a video from the 90s, where Osama is talking about his ideology and mostly Islam stuff, nothing about any attacks at all.
There is a guy called James Corbett, he has a website called thecorbettreport. He is a weird anarchist who is paranoid about surveillance technocracy, but he has great documentaries about 9/11, Al Qaeda, Osama, even some stuff like how Big Oil came to be and took over the world etc etc. I recommend his long form docs on stuff like that because he is VERY thorough with sources.