I think as long as the SPD receives enough votes to make CDU/SPD happen again, we'll inevitably end up with another Grand Coalition. Only way this won't happen is if CDU and FDP will surprisingly receive enough votes to form a coalition without needing the Greens.
But Jamaica? I just don't see it happening. They'll have coalition talks, they will try in earnest to work something out, but in the end I can't see it not imploding. CDU/Greens would be difficult enough, but CDU/FDP/Greens will be too much for the Greens to bear. When it comes down to it, they'll be too afraid to lose their identity in a conservative government.
If Jamaica fails, SPD won't have any good or even decent options left. Continuing the coalition will make sure to prolong their misery, but no one wants re-elections, either. SPD would be too afraid that the people blame them for not agreeing to a coalition, so that they receive even less votes next time around and literally everyone would be too afraid that the established parties failing to form a coalition would only help the AfD.