That would not be a split in halves, by any means, though. East Germany accounts for about 15% of the population, last I looked. Also, the far-right AfD got about 20% of the votes in the recent election. That is also not a split in halves.
Why squabble at semantics here fixating on exactly half? 1/5th of modern Germany voting for the modern incarnation of the nazi party is a disgrace and speaks to the propaganda situation their population faces.
You can see for yourself: https://bundeswahlleiterin.de/bundestagswahlen/2025/ergebnis...
This shows the winners of the "second vote."
Dark blue = CSU (conservative party), its outlines are identical to Bavaria because this party only runs there and, this time around, won 100% of the second votes.
Cyan = AfD, far right-wing party. Its outlines are nearly identical to the borders of the former GDR.
Gray = CDU, CSU's sister party, making up for most of the remainder.