Kingsport is not large, but it is layered, and it is genuinely hard to navigate without help. This wiki section covers the practical shape of the city and how to move through it without wasting the resources that a wrong turn costs you.
Kingsport is a drowned city where the vertical relationships between buildings no longer make sense. The most reliable mental model is to think of it as a set of overlapping districts rather than a street grid. Water sits at the bottom of the map, elevated platforms and rooftops sit at the top, and the connective tissue between those levels is a set of stairs, lifts and collapsed routes that shift as the story advances.
Because the fog cuts visibility to a short radius, you navigate by anchor points - a distinctive roofline, a statue, a lit window. Learning a handful of these per district is dramatically more effective than trying to trace the route on a map, because the game will make you re-trace routes you thought you knew. Where you have not been recently, assume the route has changed.
Enemy types are readable once you have seen them a few times, and most are avoidable. The game's difficulty comes from how often they appear in narrow spaces where avoidance is not possible, and from how little ammunition you have when avoidance fails. Learning which sounds telegraph which enemy is how you buy yourself the rounds to actually deal with something.
There are optional encounters and optional areas that pay out resources and artifacts at a steep cost. Taking them early, when your kit is thin, is how a run ends with an empty inventory. The community consensus is that very little in Kingsport is mandatory except what the story points you at, and even some of that can be handled without a fight.