All in all, everything worked out well. We tried to use the bikes to go the bakery in the morning, but only one of the two bikes was working. I was not sure if we missed something when trying to use the other bike but it did not seem to work.
However, we were not completely dependent on the bike as such and it was already more than expected. The flat was clean and quite nice.
People who explicitly want to visit the city center should be aware of the relatively long travel from the house (~45min), though.