You misunderstand. A librarian may not know if something is true or not, but they are educated on how to research something to find out if something is true or not. As you said, their job is to manage sources, which includes knowing with sources are reliable and which sources to look at for certain types of information.
Librarians are trained to disseminate many different kinds of information and find relevant or related media and publications, because that is literally their job. This skill can be very useful in finding relevant info for checking a news story.
Is the article listed in the "Opinion" section? Opinion is not news. Some sections are titled "Analysis" or "Political Analysis" these should be viewed as opinion. Train yourself to recognize an opinion article by reading the headline before you even click on it. Also look to see if there is a dateline at the beginning of the article. This will tell you where the news is being reported from and the source. Some will tuck it at the end where you're less likely to see it (ahem, Fox News). Some will state in the article who is the source. These sites that are 90% political news will often have reporters in Washington DC and nowhere else. Personally I avoid reading articles who's headline is a question or state what "could" happen.
Know that we all are prone to bias. In my lifetime we've gone from literally a handful of news sources to a thousand each catering to a group telling them what they want to hear. Don't be afraid to read stuff that goes against your beliefs, it will better prepare you for debating. Last and not least, for Jesus Fucking Christ don't base your opinion on memes!
The source having ties to a non-democratic government does not automatically invalidate the source, but it should make you scrutinize it more sceptically in relation to the other criteria.
I'll add another one: Are any quotes in the article or video essay being used in context? If the quoted material is crucial to the piece, have you viewed the original source?
This is mostly for TikToks and short video essays showing snippets of politicians. So much rage bait is both misquoting people on purpose and using videos that are not recent or relevant to create the correlation or narrative that they desire.