Anything short of a total ‘blue wave’ is an utter and complete failure by Democrats; the electorate tends to vote in the opposite party in the midterms (generally more motivated electorate upset about the loss, as well as putting the brakes on changes)
Anything less than a total House win and tying the Senate is failure. Abject and abysmal failure.
‘course the media will report anything as being a huge win for Democrats.
If they don’t take the House and lose seats in the Senate, even the MSM would have to admit to it being a loss.