You made a mistake in your first paragraph. It wasn’t Russia exclusively seeking a buffer zone in east Germany, it was the Soviet Union containing the Warsaw Pact region.
The Warsaw Pact region is now fully independent of the Soviet Union. So is Russia.
It’s telling that none of the Warsaw Pact region states think a buffer zone is necessary anymore, Ukraine doesn’t, the Baltics don’t, Finland didn’t, and even the anti Lukashenko parties in Belarus don’t.
Putin’s Siloviki chaps do. The Duginists do. Yanukovych did. Lukashenko already plays that part.
What does this TINY MINORITY of paranoid ethnonationalist rashist Vatnik klepto mafia types have in common that you don’t see anywhere else west of Minsk (except for a tiny political extremist faction in Serbia)?
They’re the only ones who need a justification for gangsterism. An external boogeyman. A scapegoat. Something to keep the proles in line.
Hence buffer zone against a perpetual threat of invasion that is a complete work of fiction.
Too much Gerald Ford there. I doubt the Poles and Czechs and Romanians and Hungarians really wanted to be part of Russia's security zone.
I'm not saying that Russian troops need to be in Ukraine as they were in Germany and Eastern Europe. I'm saying don't poke the bear. Don't try to make Ukraine a part of our security zone. We don't need to have troops there and talking about it is regarded as a provocation.
We (the US) also think we need a buffer zone. We would not want a hostile regime in Mexico or Central America. We put up with one in Cuba because we couldn't get rid of it.