i've used something called the "media bias fact check" to determine the left/rightness and reliable/unreliableness news sources are:

https://mediabiasfactcheck.com

I have no affiliation with them, just perplexed by the same problems everyone else here is mentioning, and it has been helpful to use.

I also think it would be helpful if reporters listed their registered political party on their bylines, ie, "John Smith, Democrat/Republican/Libertarian/etc". Or if the TV reporters wore a sign stating as much.