Calling Lenin a German spy might be a bit of a stretch but he was definitely supported by the Germans. They bought him a printing press to use in Petrograd.
After Brest Litovsk the Bolsheviks were threatened from all sides but it was uncoordinated. By the end in 1920 the Baltic states and Besserabia were free as were lots of country formed from the Austrian empire. Interestingly every new country including Germany started territory fights on their borders. Everyone wanted to revive their old empires which is why it is called the Blodlands.
In 1940 while the Germans were smashing France, which was suppose to turn into another ww1, the Soviets took the Baltic states and Besserabia/Moldava. Given this put Ploesti a 2 days march by tanks from the new border and given 60+% of German oil came from there Hitler started planning Barbarossa.
well it's called the Blood lands because that's where WWI and WWII were mainly fought on and people murdered. Not because of the post WWI land grab. It wasn't so much about empire building as in Until the mid-1800s nation states weren't a big deal in the East. There was no forced Germanization or Russification etc. until after the 1830s. Before the 1830s you had forced Franconization where Occitan was near replaced by the Parisian dialect. Similarly forced Anglicization with Gaelic and Welshe severely destroyed. But after Tsar Nicholas I you have forced Russification and the "awakening of the nations" But the problem with the "awakening of a nation" is that - let's take the territory of Romania - for nearly a millenia you had Vlachs, Magyar, Turks, Germans (Saxons mostly), Jews, Armenians, Slavs etc. all over the place. Or take Poland around "Sanok" - you had in the same town, Lemkos, Boykos, Górale Poles, lowland Poles, Germans, Jews and Armenians. Whose "land" was it? Truly speaking it was everyone's, but that's not a way to create a nation state. Hence the land grab by everyone. The anti-semitism really triggered off in this period as the Jews didn't have any land of theirs since millenia - except for Israel now under Ottoman rule. But in Russia, after they grabbed most of the Polish-Lithuanian commonwealth, they suddenly got a chunk of Jews - earlier Jews were practically non-existent in Muscowy. They decided to keep them in the Pale of Settlement and carry out their little pogroms every now and then to keep them cowed.
As to hitler’s barbarossa - I believe he had always had that in mind - Naziism was the racist-nationalist socialism that was in opposition to the Bolshevik socialism. There WOULD be a fight to the death