The issue with Germany, as it stands, is that it needs to be hobbled somehow to avoid the possibility of a conquering spree afterwards.Forget it. German nationalism was way too strong fpr anything of the kind to be possible.
The only way to have two Germanies is by one of them to be artificially propped up by foreign occupiers (like the GDR later) and doomed to collapse as soon as the foreign occupiers leave. Otherwise no point in even talking about it.
Either you take one of its main industrial basins away (Silesia to Czechoslovakia/Poland, or Inter-Allied Rhineland ?), either you reduce significantly its territorial extent and demographic pull (ie remove the three South German states and MAYBE Hannover) to shrink its manpower base, either you put army limits.
The first leaves at least one of the potential targets of Germany with a very significant and restive German minority, the second leaves multiple German countries outside North Germany's borders which may just reunite or ally out of convenience, and the third needs to be enforced.
It isn't easy, since on the medium-term only continental powers (esp. France) have an interest in keeping Germany down.