Stacked cable pass-through that allows connectors as well?
I swear I designed almost the same thing, haha.
Eventually I got to a level of complexity (when I started planning for waterproofing) whereI knew it would be less painful to use an off the shelf solution. I had glands installed and wires routed in less time it took to design the first prototype, haha.
But I really wanted to see how well it would work. Please print it and report back!
Edit: Hereās my version:
I planned to have another layer on the backside in order to sandwich butyl tape in the center (same plane as the enclosure wall) for waterproofing.
Fasteners (qty 2) in the center minimizes the number of holes / leak paths in the whole thing. You could also move your fastener holes outwards and put a shallow channel for silicone on the interior side of those holes.