Cities: Skylines 2 continues to lumber toward proper completion with another new patch fixing a handful of issues—including problems with custom climates, and an issue that was causing tool modes to disappear. Alas, your city's hoteliers will remain unhappy, because their problems remain unsolved.
The problem for your hospitality industry isn't actually a lack of lodgers, it's that even when all rooms are occupied, hotels will still complain about "not enough customers," an issue that apparently arises because the "Lodging" resource is consumed too slowly. Colossal Order is working on a fix for that, but it wasn't ready in time for this patch—it'll be included in a subsequent patch once it's passed testing.
