I tend to read more sources that look at the world from a MAGA Republican perspective. Given that, a whole bunch of commenters appear to think that recent debates in PA, NY, MI, etc. didn’t go well for Democrats. Plus the left-leaning MSM isn’t touting any of these as successes for their side.
Even MSM sources appear to believe that Fetterman did himself some serious harm in the PA Senate race debate against Oz. The Zeldin-Hochul debate in NY apparently did her no favors. In AZ the Dem. refused to debate, not a good look.
Some of it is individual candidate weakness, but most of it is that the issues all the polls say voters care about most are issues voters believe Republicans are better at solving. In a debate Republicans hammer away on crime and cost of living and Democrats mostly have no come-backs that find a widely receptive audience.