Is there any possible way we could have a config to turn on the boundary tiles as placeable tiles? I find myself often using the sides of a chest as well as the front. This is less about having more room period and more about having space around the chests/connections. I'd even be fine sacrificing more room just to have the chest/connection pushed inwards by one tile tbh.

A temporary solution for newly placed factories is to replace in the layout.lua file factory-wall-N with factory-pattern-N.

EDIT:
Better solution:
Go to prototypes/tiles.lua, and then edit the mask of each wall. Replace edge_mask() with floor_mask() for each wall, or whatever collision mask the pattern/floor tiles use.