From what I can tell covid related restrictions and requirements for tourist related activities vary Land by Land. I believe that throughout Bavaria for instance, non-vaccinated must have a negative test to stay in accomodations, whereas in Baden Wurttemberg that requirement has been waived for all regions below a certain threshold. Is there a good site that summarizes all the differences by Land?
Rob, it is varying. Things are changing all the time. Right now things are pretty lax, but for instance Spain was just put back on the RKI Risk List starting this Sunday. The Delta Variant has arrived in Germany. Probably have to call direct to the German hotel. Their websites in many cases are not keeping up. In some cases it depends on the hotel. When a test is required, some are accepting the 1/2 hour fast test you can buy at a suppermarket or drug store. Not sure how accurate anything you find on the Net is.
I have not seen anything like this. The thing is, as your post suggests you know, it is not even just Bundesland-by-Bundesland, but actually Landkreis-by-Landkreis that the regulations differ, because the basic rules are applied based on incidence rates at the Landkreis level. And, in at least some Bundesländer, I believe localities have a bit of freedom as well.
So: I think calling or emailing hotels is the best thing to do. Also, most towns have good coronavirus portals that summarise all the rules in force in that town, based on the Bunedsland rules and the local incidence rate and whatever else. This is what I have been using recently when I travel regionally.