A sea change began with Walter Lippmann's Public Opinion, seen as birthing modern, generally impartial, journalism. Not absolutely, but relative to earlier periods, quite.
Ironically, widespread national advertising assisted in much of. this, at least for stories not adversely concerning national advertisers. But local squelching of critical news was limited, and occasional nationally critical stories could appear. Watergate was arguably the high-water mark. Corporate ownership massively diluted effectiveness, especially after 1980, though exceptions remain.
Bookending Orwell and Lippmann, I'd suggest I.F. Stone (who calls the 1970s as a high-water mark) and Hamilton Holt's Commercialism and Journalism (1909).
I.F. Stone, interview: https://www.invidio.us/watch?v=qV3gO3zxQ1g
textsCommercialism and journalism https://archive.org/details/commercialismjou00holtuoft
Further reading:
https://old.reddit.com/r/dredmorbius/comments/7k7l4m/media_a...
"This kind of thing is frightening to me, because it often gives me the feeling that the very concept of objective truth is fading out of the world. [...] I know it is the fashion to say that most of recorded history is lies anyway. I am willing to believe that history is for the most part inaccurate and biased, but what is peculiar to our own age is the abandonment of the idea that history could be truthfully written. In the past people deliberately lied, or they unconsciously coloured what they wrote, or they struggled after the truth, well knowing that they must make many mistakes; but in each case they believed that ‘the facts’ existed and were more or less discoverable."
--- George Orwell, 1942