During the validity of your pass, you have the right to travel two days in  your own country. So yes, you could use them. But then you won’t have any days left, for the journey back.

If I were you, I would use the pass for the most expensive stretches in Germany (probably Cologne-Munchen). And buy an ordinary ticket München - first station in Austria, probably won’t be that much. And start using your pass again in Austria.