This. Early trees sequestered a whole bunch of carbon in their structure (and there wasn’t efficient methods of breaking down lignin at the time, so the carbon stayed in the ground instead of rotting and returning to the sky). If we build long-lived structures out of wood or other carbon bearing materials whose carbon source is the atmosphere, we’ll be doing the same thing as trees but with human civilization as the organism.

Sounds like the real question is, how does 1 hectare of stick frame buildings compare to 1 hectare of mature forest? What stores more carbon-per-hectare, and how many years does the building actually lock up that carbon?

While a hectare of forest may be "only" CO2-neutral, a hectare of buildings are typically net CO2 emitters.