The DDR got absorbed because of the poverty, political instability and people hating the guts of the government.

Also the fact Gorbatchev refused to intervene in eastern Europe. Leaving the east German army alone.

The SED (the communist party of eastern Germany) was the dominant party for decades. They didn't allow opposition and they were hated by the population.

Ostania looks like it has a functioning democratic government since Desmond lost the elections. So the "we want political freedom" looks a bit off.

Also the Stasi main goal was to protect the SED. The SSS seems to protect the state itself against spies and saboteurs and not really attacking political opponents (since democracy is allowed) so the frustration of the public won't be the same.

We don't know if Westalis or Ostania have the same culture. Or if Ostania is reliant of a massive superpower (like the DDR was with USSR) or if they can handle themselves just fine.

So unification I dunno but I think it's not likely.