Yeah. I eventually resorted to having a squad of units to act as a construction crew, 6 to go out and block the flow of enemies, 6 to team build the buildings. A strategy I developed because the system that made units return to their prior actions would somehow permanently disable their ability to engage in combat. The solution was lost in the spaghetti, but thinking about it now, I should just turn off the area2D,s monitoring while building.
Don't be sorry about the screenshot thing. It means a ton that you gave it yet another try. Thank you so much for all the valuable input and encouragement.