I made another bread, and what a difference.
First I think that despite having followed the recipe, the starter wasn’t ready yet the last time. This time the dough already felt very different when I first mixed everything together. During the subsequent kneadings it would be much lighter, too, and I had to shorten the final resting time from 5-6 hours to 2.5, because otherwise it would have run out of the bowl (that worked nicely, thank you). I also preheated the stone thoroughly and look how this turned out. I also added black caraway seed and rosemary and that is delicious.