I looked and I see you are doing almost exactly what I think I want to do. I thought it would be good to make a kind of long “stick” with motors and pulleys inside and to use 12 identical sticks. I’m also thinking to make it easy to change from 6:1 to 9:1 and to somehow fit sensors in the stick.
One thing I have is a Harbor Fright mini milling machine converted to CNC. The mill is not ultra-high precision, but is slightly better then a 3D printer. So I have the option to make metal CNC parts. But I would 3D print prototypes. Metal parts would be good for both thermal and structure reasons.
I’d like to see your motor drivers. I think DRV8316 chips could work but I wonder what current you supply to motors and how feedback works.
I don’t want to copy your robot exactly, even if it is a full generation ahead of mine and it is. But if you want to collaberate on a future iteration with profesional-level CAD and software. I’m up for it. I’m using Fusion360 now but I’m trying to switch to FreeCAD and KiCad so as to make a 100% free tool chain that runs native on Linux. I’m doing a few FreeCAD tutorials today