The problem with "tools to distinguish who's worth listening to" is that, as you said, "its an impossible judgement to make and its impossible to find a fair judge."
No individual can be knowledgeable in all the areas of science, economics, medicine, technology, etc, that would be necessary to understand and filter even a tiny slice of the daily news. Any tool will necessarily be making judgment calls for it's users in some way, and once the tool becomes the standard, those judgments will (effectively if perhaps not literally) determine who gets banned.
You are right. This isnt easy, but i do think there are some things worth exploring:
Science isn't controlled by one body, but by a network of peers that reaffirms or disproves prior work. Over time consensus is built, without the need to silence.
Right now we use clicks as proxy for value. What if we structured it differently like, give people a limited pot of recommendation tokens they could use to show others what they value. If someone gives 3 months of tokens to a 10 page article, maybe that's worth reading?
I dont know if these are the right metrics but we need to experiment.
YouTube did the opposit when they wanted to reach 1 billion hours a day: they promoted anyone who had a channel that produced 1h of content a day. That meant that all the alternative news/facts talk-shows got a huge boost and that lead to a lot of bad things.
No individual can be knowledgeable in all the areas of science, economics, medicine, technology, etc, that would be necessary to understand and filter even a tiny slice of the daily news. Any tool will necessarily be making judgment calls for it's users in some way, and once the tool becomes the standard, those judgments will (effectively if perhaps not literally) determine who gets banned.