I agree that "misinformation" is a somewhat narrow & misleading way to frame the problem, as though there are just bits of bad information mixed in the good stuff. In practical terms, the real problem is "lack of reliable, shared information sources."
The "shared" part is, IMO, even more important than the "accurate" part. A society can survive for a long time with everyone believing common myths, even if the myths are false, but it can't survive long with everyone believing their own custom-designed bespoke myths.
Basically, a functioning society needs trusted epistemic authorities. It's just not workable for everyone to be their own freelance truth finder, however attractive that romantic notion might be to some people.