One can argue that bias exists in what stories get picked up. For example, I would read Breitbart back in 2016 to see what they're up to. And they would have a ton of stories about violence against the police. They saw that as a counter to all the stories about police abuse that we see in mainstream media.
Ideological leaning affects what people see as newsworthy.
Those do exist. There can be that based on who is assigning stories.
All of the presidential elections in my life the winner has had more positive and more overall articles written about them. Generally news publishes what people are interested in reading. The more popular candidate usually wins. People definitely point to a liberal bias when a democrat wins the presidency but ignore the fact that news had a conservative bias the years a republican candidate won.
Bias's definitely exist. But acting like its a huge conspiracy and countering that with garbage news with an agenda like fox news and breitbart is just silly.