To make it easier for the haulers, I sort my flattened cardboard boxes by size, and then insert the smaller ones within the larger ones, rotated 90 degrees. That way, they can grab larger bundles at once.
To me, this is less effort than the Japanese approach of using twine to tie bundles of cardboard together.
We have to put paper waste into plastic bags provided by the company, around 120 liters in size. So any larger boxes need to be not onpy flattened but torn before they fit into these bags. It’s a workout.