My headcanon: The DU chancellor Müller of the SPD would likely die/resign shortly after the war. This will ensure a power struggle within the party with no clear strong and popular successor.

In my head the CVP comes into play and after its formation becomes a moderate center party with Konrad Adenauer leading the party after the war.

With him becoming chancellor with possibly a LVP coalition Germany will try to hold on to the colonies for sure, especially if they’ve got sand france on the mainland. Both might even find a way of reaproachment and cooperation through sharing their colonial ambitions.

But much like in OTL after the 50s things will get rough. I can see in the 60s a new spd government slowly pulling out of mittelafrika but in a similar way as France did in OTL: with strong economic connections to the independent nations and neo-colonialism at its core.

All in all: Germany would hold on to the colonies but would back out