You see, it's all about gauging interest, and that determines what appears on the news, no matter the station. For example, Fox News mostly has a nationalist center-right audience, so covering things like Hunter Biden, Biden's gaffes, or isolationist stories tend to be more profitable. Meanwhile, NBC and CBS tend to have a more liberal audience, but not extremely so, so coverage on global events and stuff that affects America from the outside suit their viewers best. CNN has a center-left nationalist audience, so they tend to profit off of Never Trump types of stories as well as Congress discussions. MSNBC is pretty far left, so they like to cover the typical woke bull.
CNN and MSNBC will not dare touch anything that makes Biden look bad, while the viewers of shows like CBS and NBC wouldn't tend to be interested since they are more interested in the global perspective. Fox News, though, with a dislike for Biden, will gladly take any shot at mudslinging that they can. Note that I never mentioned ABC because I don't think I ever really heard them do any news other than that George Stephanopoulos (or whatever his last name is) and I honestly don't know enough about it.