I indeed meant the situation after "Bagration", which admittedly occurred a month later than the D-Day. In July there was impression that German defenses in Eastern front utterly collapsed and the war might end in 1944 - until they managed to stabilize front line in Poland. But even in June it was understood that Germany's position is hopeless and they won't be able to hold USSR for long.That calculus changed after the colossal victories of July and August, but by then virtually everything about the situation had changed.
And I'm not trying to downplay the importance of second front for the USSR, it helped a lot and saved many lives of Soviet people. Just it could save much more if it was opened a year or two earlier.