So clearly the way the original game implemented these rooms is to have two maps, one for the room interiors and one for the rest of the floor, and swap you between them at the threshold
The second reason is, yeah, a lot of the game's difficulty comes from being worn down by attrition as you navigate a dungeon full of dead ends you can't see until you walk down them
to the point where it was honestly optimal (without a guide) to do one run to figure out the route to the boss, return to the surface, Cottage, and then do one straight shot to the boss
A clear thirty years in the making.