I speak Japanese and, at least for all the words I’m thinking of for both cow and vagina, none come out to awesome unless it’s some net slang that I don’t know. Cow could by Gyuu or Ushi. Vagina is often mata, man, or manko (all of which could have a preceding ‘o’) (edit: also chitsu and wagina (probably by way of Dutch originally), apparently also exist.) Those might possibly work better, especially wagina with the -na ending common to a type of adjective)

Awesome is a bit trickier. Subarashii is usually the dictionary one, but Sogoi/sugei or saikou come to mind. Archaic rippaa also exists. If that’s true, my vote is on net slang or just something I’m totally not seeing.

Edit: after filling my search history with interesting things, it appears it’s Chinese and not Japanese. “niubi”.

https://www.urbandictionary.com/define.php?term=VTuber

and you know what a cow is