I wouldn't call the criterion for a good paper "never reports anything inaccurate" as news are written by humans and humans are fallible, but rather "is able to admit mistakes and will put effort into clarifying rather than covering them". Also I would criticise the term "not reporting anything bad" - that could also be interpreted as not reporting anything that could speak against the government, for example. Instead I would recommend "acts according to some set of morals" as a criterion - in Germany we have a "Press Code" that every journalist learns and that is also being observed by the German Press Council. Another note: I think there cannot exist such a thing as the one perfect paper, because there does not exist one perfect opinion or viewpoint. The purpose of a good paper is to bring that into account: To picture different, maybe yet unseen perspectives on a problem. A set of high quality papers with different focuses existing alongside each other is a good thing for the same reason.

One paper that does a great job in my opinion is "Die Zeit". I am not familiar with the American media landscape and thus a equivalent, however.

> inaccurate and unreliable in other things

They aren't often though, because they stake their reputation on being accurate.

Bias is harmful, but I think the WaPo and NYT are a much more acceptable level of bias then say, Fox.

Acceptable for those that agree with them, sure. Ask somebody who does not. And there is very little penalty for them for being inaccurate or biased if inaccuracy and bias aligns with biases of their audience, which are pretty clearly partisan. Do you know many Democrats that would stop reading NYT because they were hitting too hard on Trump or reported some news with anti-Republican bias? I don't think there are too many such people.