You need to divorce the news part from the opinion part.
News channels have 2 sorts of programming. They have the actual news bulletins, where a news anchor at a desk reads out the stories of the day with reporters on the ground fleshing out those stories on location.
Thats the smaller fraction of their programming.
Then there is the opinion shows. A rotating cast of talking heads offer their opinions about the stories of the day, and those opinions are routinely coloured by the editorial bias of the channel in question.
Of all the 24 hour news channels, none is more biased in it's opinions than Fox.
Fox News, the actual news part is usually reasonably accurate. The news is covered by all of the media so they tend to stick to the accepted facts for their news bulletins. Every so often you'll see something like Fox calling Arizona for Biden for example.
Fox News opinion shows frequently make **** up. They make **** up because it lets them get lots of viewers and no other mainstream news channel goes after the right wing viewers.
See this
recent case about Tucker Carlson
They stick closer to the facts for their bulletins to make their opinion content appear more credible. If they made **** up about the actual news, stories that were very easy to show were utterly false then that would turn viewers off the channel as a whole.
All Fox cares about is market share and making money. No more, no less. Like them or not they are certainly very good at that.
They have a big market share because they pander to the right wing nut job market share that noone else wants to go for.
Their market share has no bearing on the accuracy or veracity of either their news bulletins or their opinion shows.