I don't know much about CNN, and don't watch Fox, but from what I've heard the actual news segments on Fox aren't as bad, it's the opinion shows (most of which masquerade as news) that are the bad bit.
In the UK we have several popular news channels and each has their own leanings, and while I think it's important that viewers are mindful of those leanings, I don't think it's too far out there to say that one can assume they are not being out-right lied to, and it's rare for a news channel to ever say something actually dangerous. There are issues, there are complaints made, but then there are typically retractions and the issues are fairly rare, compared to what I've seen of US media.
Again I think there's a place for blogging, factual videos on TikTok, people working their way into the industry more organically, and special interest groups, etc. But I do think there's a need for the bulk of mainstream news to live up to the responsibility they have to the public.
While there will be some bias from being challenged, I think there's also plenty of good reasons for journalists to challenge these sorts of companies.
Journalism is a profession and brings with it a lot of ethical considerations. Teaching of journalism goes into depth on why the ethics are important, how to report on sensitive topics, and all sorts that makes journalists far better qualified to report on things.
There's absolutely a place for self-taught/hobbyist writing, but it's not journalism, and if we depend on it for the "important" or hard topics we'll lose out on the benefits that well trained journalists bring to the table.