Yep, even when it comes to Fallout 4, the fact that Far Harbor was large enough to contain all of the necessary elements to build a cool new cohesive location, expand on playstyles, and provide a complete narrative vs how empty Nuka World and Automatron were is where I draw big inspiration.
Shadow of the Erdtree has frustrating parts, but is ultimately a prime example of an Expansion vs DLC. Same with Phantom Liberty, for the same reasons as Far Harbor.