I would tread very carefully about how you think of "bias" and objectivity.

If you synthesize points of view from a variety of different news sources(left leaning, mainstream, right leaning) and leave out stories which are only being reported by one or two sources, that could still lead to a strong centrist/establishment bias. Being biased towards the middle is still a bias.

For example, after 9/11 the majority of news sources in the US were(knowingly or not) pushing US government propaganda about WMDs. A news AI trained to provide a synthesis of several different sources might've done the exact same thing if that's what most of the data pointss included in the synthesis are doing.

It's arguably better for a news source to declare biases openly than it is for a news source to pretend to be "bias free".

Rather than focus on being neutral, I think it's better to focus on factual accuracy and complex, in-depth analysis. The problem with CNN and Fox News isn't so much that they're biased as it is that they're often very sloppy with fact checking and pushing very oversimplified clickbait narratives.

There are "biased" sources which still consistently produce complex, factually accurate coverage and analysis of events, like Jacobin on the left or the Economist on the right.