https://www.nytimes.com/2023/11/08/upshot/biden-election-results-2024.html
For the pessimistic version of 2024, the electorate for low turnout off-cycle elections tends to be more engaged Democrats than during the presidential election. Especially in recent years as education has become a clear partisan dividing line.
So while we can learn a lot from the 2023 elections, we shouldn't extrapolate them too much.
And as Nate mentions, everything that happened on Tuesday was in line with the polling. Issue 1 was favored in Ohio in the polls. Beshear was favored in Kentucky. So it wasn't evidence of polling being wrong- quite the opposite.
Where I would diverge from Nate here, I don't think general election polling this early is very predictive. Not to say Biden is in a great place. Just that I don't think we can really say what it will be like till the general election campaigning gets under way. Particularly because the exact disengaged voters that don't vote in these off-cycle races haven't really been confronted with the 2024 race yet.