Developer: I have a meeting with architects and lots of small repos Vs one HUGE repo is what we’re talking about.
Me: So the big question is how do you wanna split your huge set of code? In one or many things?
The number of things to track in your head remains the same. You either keep track of many folders in one repo or many repos. The cognitive load is about equal. The pain is in the discussion of it.
Just pick something and then iterate as needed.