So Germany lost ww1 like IOTL, are blamed for war, TOV still happened, but with some subtle changes-that is first change-Poles have worse negotiation position (more invilved fighting on CP side perhaps? Or vassal Kingdom of Poland with Charles Stephen Habsburg already created by CP? Piłsudski fights on CP side to the bitter end? Wilson is less fixated about nations' self-determination and does not mentioned creation of Polish state with free access to the see? Combination of all these points?) Thus they only get Posen in TOV. Second change-Czechs and Slovaks created separate states, no Czechoslovakia (and propably bigger Hungary as result, with Southern Slovakia and Carpathian Ruthenia still under Hungarian rule.
Third change-weaker Poland of TTL could not withstand Soviet invasion, thus there is need to weaken Bolsheviks as well to counterbalance it. Longer Russian Civil war with narrower Red victory is needed then (maybe this point could be joined with first one-Whites do better, so France do not insist so strong to strenght their ersatz allies in Central Europe). So during 1920s we have weaker Central European states-Czech Republic, Slovakia, smaller Poland. Would Germany puppetize them over time and how would it impact internal situation of Germany? Would we see French-Soviet alliance? If Germany manages to vassalize its eastern neighbors there is no place for German-Soviet alliance, while Soviets and France both would feel threatened.