We bought refundable tickets on united/lufthansa last week from Sacramento to Frankfurt, return Munich to Sacramento via Denver both flights, late August thru late September,24 days on the ground. Want to visit Bonn possibly, for sure Heidelberg, Black Forest region including Freiburg, potentially going into Switzerland with Luzern, Thun, Grindelwald, Bern, perhaps the Ticino region on the list. If we don't do Switzerland more time for Germany in which case we'd probably visit more in Baden Wurttemberg, plus maybe more in Hessen and Rheinland area. Looking at fully cancelable accomodations as we get closer to time, and as most of our potential travelling in Germany will be in short stretches probably lots of day tickets.
I have found that there isn't too much of a price difference for Deutsche Bahn ic tickets for short stretches, as they only go so low if you buy them months beforehand and don't seem that high if you buy them close to travel date. For Switzerland however, on some routes that I'm looking at there are bigger differences based on purchase time. If things seem to be tightening up closer to time, with cases on the rise and a greater degree of travel uncertainty, we would cancel things, but right now its full steam ahead, just got to figure out where we want to go.