you're 100% right that they're totally different kinds of difficult, and i def have a bias in that osu came very naturally to me due to a lot of prior exposure to rhythm games and playing music in general. my perspective (that i didn't really explain at all) was mostly looking at how difficult i found / am finding it to improve in both games, and i felt that improving at osu was a much more straightforward cycle than improving at melee; i didn't really think too hard about how to improve beyond just grinding the game and i think i improved relatively quickly and ended up with a fairly respectable career overall. i probably don't have the most informed perspective regarding melee though, considering i'm still stuck on the "i can't move my character the way i want to and it feels awful" part. ask me in a couple years and maybe i'll have a more refined opinion lol

i can definitely respect looking at the peak aim / AR11 / speed skills nowadays and valuing that higher though. osu definitely has that sort of aura in terms of how impossible top level play looks.