I disagree with your sentiment about Google News. I think it does a great job of aggregating all the sources to a given headline. It even goes as far as labeling the sources as "Opinion pieces", "Highly Cited", or even "From ___" opposing entity sources (eg. From Saudi Arabia sources).
There is no easy answer to to display ONLY unbiased sources, because that would require an unbiased source to pull from. Which I don't believe exists. With Google News, responsibility falls on the reader to use the sources in front of them to formulate an educated opinion and gain an understanding of the story. If a reader chooses to only view either right-wing or leftist sources via Google News, then that's beyond Google's control.
We seem to be expecting technology to allow us to cast media literacy to the wind, but that's not going to happen. I don't happen to be a google news user, but it strikes me as providing the opportunity for the user to either remain in an echo chamber (for any given story, you can read the article from your outlet of choice, for example), or to diversify what you consume. Technology is one tool that people use to spread disinformation, propaganda, and bias, but it's just a tool. Similarly, technology is one way to fight it, but it's just one way—I think we could all use a reminder on how to be a savvy consumer of news media. Most people don't seem to appreciate the difference between an outlet covering a story versus breaking it, or how sourcing and citing work, the difference between opinion articles, analysis and reportage, and so on.
Well, offloading responsibility gets you nowhere. It doesn't solve the problem, it simply ignores it. What value is there in aggregation if there is no standard of quality?
There is no easy answer to to display ONLY unbiased sources, because that would require an unbiased source to pull from. Which I don't believe exists. With Google News, responsibility falls on the reader to use the sources in front of them to formulate an educated opinion and gain an understanding of the story. If a reader chooses to only view either right-wing or leftist sources via Google News, then that's beyond Google's control.