That's funny, when I read the hebrew sentence, I immediately translated it to mean, "The king goes (like travels) by way of the water".... But it would need to say "דרך המים" for that, wouldn't it? Or maybe he always travels by way of water (=דרך מים)... I don't know.....
I think it can be both: בְּדֶ֫רֶךְ כְּלָל שֶׁאֲנִי נָע דֶּ֫רֶךְ מַ֫יִם אֲנִי בְּסִירַת־מָנוֹעַ Usually, when I travel by water, I am in a motorboat, but also אֵ֫יזֶה סוּג שֶׁל עַרְפָּד יָכוֹל לְהִסְתּוֹבֵב בְּאוֹר־הַיּוֹם וְלַחֲצוֹת דֶּ֫רֶךְ מַ֫יִם what sort of vampire can walk around in the daylight and cross through water?
This reminds me of the Sir Walter Raleigh incident in which he lays his cloak on a puddle for Queen Elizabeth to trod upon. I imagine that Duolingo changed “queen” to “king” because we haven’t learn “queen” yet. And then the incident got changed further when the monarch didn’t even get the cloak!