After civil war Russia was divided between Reds and Whites-Poland helped Whites under condition that they will agree for Polish eastern border along Dmowski Line (OTL border of Second Polish Republic plus Minsk and Kamieniec), weakened Russia is not danger for Poland. After Nazi collapse (say France turns facist, allied with Italy, Poland and Czechoslovakia, blocked Nazi attemps to expand at cost of Austria and Czechia, leading to Reich bankruptcy) Poland seize opportunity to get Danzig, Upper Silesia and Masuria.