The host in some of these videos (such as the interviews with Mao Fujita and Daniil Trifonov) is kind of interesting. he was interviewed (for a change) here I think he has interesting perspective on starting later than a lot of the famous pianists (age 9), then Sergei Babayan accepting him as a student at Cleveland Institute (Daniil Trifonov was his upstairs neighbor).
My favorite full documentary is Horowitz the Last Romantic:
It's unique in that most documentaries have a priority of furthering a 'profound genius musician' kind of aura for whoever the pianist is and trying to build up a legacy. It gets to a point the seriousness and level of formality is too much. So to see one of the greatest pianists being so casual and being that unpretentious is heartwarming. The legacy is so taken for granted the documentary can just let him be himself. The people from Steinway or his management company like Peter Gelb also talk to him so normally. I think classical music interviewers lay it on very thick, leading into questions with over the top compliments.