You make it sound like Germany weaponised an oblivious Lenin by letting him loose on Russia. In reality, Lenin observed the February revolution from afar and realized it was a critical time to rejoin the struggle, and petitioned the German government to leave; the Germans agreed because it was strategically advantageous for them to allow dissidents to travel into Russia. The so-called "sealed" train was a cover story [1].

[1] https://www.newyorker.com/culture/culture-desk/lenin-and-the...