G-code file was exported for MK3S+ MMU3, with generic PETG filament profile.
MMU3 extruder 1: white color
MMU3 extruder 2: black color
Print settings: 0.15 mm QUALITY, 25% infill, 0.4 mm nozzle.
Note that print orientation is face down (same as in provided STL files), to obtain nice flat finish.
The author remixed this model.
I separated STL file for white and black colors. Also, flattened the model and turned face down, to get nicer finish.