Youtube hands down. Youtube is the best dad, best teacher, biggest information hub, and arguably the best meme generator in existence. The fact i can dive into any type of video content and come out feeling like i gained so much is incredible.
Depending on how you look at it then yes its not free. Though you could use something like Libretube to prevent both ads and any form of analytical data from being collected.
Though other alternatives like revanced manager prevent ads and give premium benefits. Not sure about the analytical instance of it though.
You just have to curate the auto-suggestions. After a little while mine basically only suggests me educational/science videos and movie reviews/analysis.