Upvote:-3
The Molotov-von Ribbentrop treaty was the culmination of over a decade of good relations between Germany and the USSR.
What changes there would be to the public perception (and thus propaganda) would be gradual, not sudden. Sudden massive changes in propaganda generally don't work, you need to build it up over time if you have a target population who are at all intelligent (so not a Tiktok generation) and especially if they may have access to other sources of information next to your own.
Obviously it IS possible to suddenly change an attitude with shock events, as happened on the outset of WW2 with false flag operations against Poland and later the USSR, but even then a gradual buildup of hostile sentiment is generally to be preferred. And remember that the German people were already not very friendly with the Poles, and communists (rather than the Soviet government, who both the German propaganda pre-Barbarossa and the western propaganda pre-1945 did not mention were communists) were already not in high favour in Germany.
I've not made a deep study of German propaganda re the USSR during that short period but what I have seen doesn't strike me as a major shift in content or purpose, nothing like what happened in the period around the start of Barbarossa.
Also remember that Hitler and Stalin admired one another for what they had achieved (even if it is doubtful you could ever call them friends). Something that was written out of history by British and American propaganda post-Barbarossa because "Uncle Joe" had to be portrayed as the staunch anti-Hitler bulwark who could do no wrong (boy how that changed post-WW2) and thus any ideological or economic ties between Germany and the USSR had to be forgotten.