That makes it sound like suburbia is a large patchwork of “suburb” and “edge of the suburbs”. Definitely not how I would understand it as a european.

Regardless of what OP meant, I would personally care about the overall density of all places people commonly need to get to or through, compared for us and european suburbia.
So counting houses, roads, regulatorilly demanded greenspace padding, sidewalks, shops, recreation, utilities. Maybe even parks.