It is not true ..
"In 1934, Hitler himself had spoken of an inescapable battle against both Pan-Slavism and Neo-Slavism, the victory in which would lead to "permanent mastery of the world", though he stated that they would "walk part of the road with the Russians, if that will help us.""
History only happens once, alternative branches are ruthlessly pruned by the things that actually happen and we have no way of knowing what would have happened for any of the other branches.
The fact that he said it in 1934 but waited until one week after the signing of the pact gives some doubt about whether or not he would have done it if the Russians hadn't signed.
Anyway, in 1938 Germany and Poland partitioned Czechoslovakia in the same way Poland would be handled year later. At this event Polish minister Beck said that Czechoslovakia is not a real country anyway, giving tacit approval to total German occupation. No one however would claim German incursion could be avoided if not Polish participation.
It was nearly identical situation in 1939, only the scale was bigger and some shots finally fired.
Not quite idential.
Incidentally, I was in Prague 2 days ago, what a beautiful city it is.
Never been to Czech yet, but I've spent three fine days in Krakow last month. Beautiful town, fortunately left mostly intact in the war.
There are lots of nice cities in Poland.