to be fair, we shouldn't trust only one source just because it's fact-checked. for the best practice, gather the same news reports from multiple sources, regardless of fact-checking or the reliability of its source. if the fact-check only contains primary sources (or sources coming from allies but nothing from opposites just because they aren't reliable, especially regarding conspiracies), they too could be a conspiracy.

assuming there are two fact-checkers who have a contrasting conclusion, both get reliable sources, who are we going to trust?

for example, this article about covid vax deaths i have linked before also contains numerous sources on their claims. no matter how misrepresented to you, under your logic, this too should be considered a fact-check.