I recently did some cable management on a RatRig V-Core 3 and found myself in search for a minimalistic solution to keep cables within common 3030 profiles. There were no models to my liking so I designed one.
Consider exporting your own STL from the attached Fusion 360 file in order to match your set thin wall thickness. The given STL is meant to be printed with 0.45mm (external) perimeter width, so that you get a recommended thin wall thickness of 0.85mm at two perimeters (PrusaSlicer).
The author marked this model as their own original creation.