The night before we left for Switzerland, the CDC made Switzerland a level 4 country. We were all packed and ready to go. After an initial primal scream, a professional medical researcher friend looked at the rates of infection, and determined the risk to be the same as our hometown area. So we went. Once we were there, it was a great trip and except for mask wearing, we weren't too impacted, until it was time to test for returning home. A little stressful thinking about the testing, but we had the Emed BinaxNow proctored tests with us, and it was easy.
Your circumstances are a bit different, as the infection rates in areas of Germany are now higher than they were in Sept for us. Most likely your concerns would center on the country being completely locked down and your not being able to get home, or a breakthrough infection and testing positive??? I do know that resistance to restrictions was very high in Switzerland when we were there, and actually witnessed a peaceful demonstration in Bern.
I guess it comes down to your cancelation dates for hotels, your travel insurance coverage if you're going to a level 4 country, and how well you can handle coming down to the last minutes to make your decision.
I so feel your pain because we lived through the same experiences. Good luck again!