The video documents Legendary Ocarina of Time Speedrunner Cosmo Wright's descent into irrelevance and madness. I'd never heard of Cosmo Wright before, but usually watch Cecil McFly's documentaries because they are always well researched and interesting.
This one was really strange it covered years of a streamer, not only being mentally ill, but also losing the skills that made them famous in the first place due to Carpal Tunnel and then getting banned from everywhere. The only video I could compare it to is the documentary about the Worlds Worst Guitarist.