I spend a lot of my idle time “working” on different problems with projects I have going on and a lot of that involves “constructing” things in my mind.

I do, too! I guess in a different way though. A lot of aphants like to compare it to a computer that does not have a screen or GUI. The computer is there - also the graphics card, the images, the data - but nothing visual appears in your mind’s eye. I would say there are several things that are more difficult for me to do - but surprisingly people with aphantasia function just fine. Otherwise I would have known something is different with me way earlier.