Every album I’ve ever encountered seems to have a mixture of bangers and one or more meh or outright flops. It’s easier than ever to skip over the tracks now, but as the question asks: what’s is, in your opinion, the perfect album, or does one/can one even exist?
Alt rock is broad, but if we’re going with grunge, I’d say Nevermind, although purists will say that’s not totally grunge. You run into similar issues with Ten. Both albums are insanely good start to finish though.
In terms of movies, Bernard Hermann or Ennio Moriconne. Both had some bombs and also some bomb ass stuff. When they were on point they were amazing.