"...If you take that approach and add Musk's source truthfulness rating[1]..."
Not sure resurrecting Pravda is the best way to ascertain the veracity of facts with authority. Pravda was a joke.
That said, the unfortunate reality is that ALL of these proposals are predicated on trust. Do you trust whatever news source you are consuming? Do you trust whatever news source rating platform you are consuming? Etc etc.
Nowadays, it's probably best just to accept that every article or comment you see on the internet is possibly part of a well tuned professional manipulation campaign. This goes DOUBLY for any article or comment that is even remotely political. Including this comment, your comment, and every other comment on this thread.
That's just the nature of the world in which we currently live. A sad reality is that, in the end, we'll all be effectively choosing the sources, the data and the stories we wish to believe. And those choices will be largely informed by our pre-existing biases.