>What specific kinds of queries does it do badly at?
in my experience all of them, because the experience for me currently is that youtube surfaces ~3 videos relevant to the search I entered, then the bizarre category of "here's other stuff you want to watch" (I don't) followed by "stuff you already watched but want to watch again" (I don't and didn't ask), followed by like 10 shorts and then again a handful of results relevant to the query
I haven't noticed this because in all of the above examples the first result is the one I want, almost without exception. In a scenario where the top result or two is correct, showing other stuff after result 3 doesn't sound that bad.
What sorts of searches are you doing? My guess is this really matters and that you're using search for a completely different purpose to me, but I don't know what that is.
in my experience all of them, because the experience for me currently is that youtube surfaces ~3 videos relevant to the search I entered, then the bizarre category of "here's other stuff you want to watch" (I don't) followed by "stuff you already watched but want to watch again" (I don't and didn't ask), followed by like 10 shorts and then again a handful of results relevant to the query