Load the .3mf in Bambu Studio. Set flushing volumes to 800 both ways. Set flow for the interface material at 105%
I used PETG and PLA Plus
Note the modifier layer on either side of the "support" layers, this is to force the creation of top and bottom layers of the base grid parts, otherwise the slicer will treat the intermediate layer as just a modifier with infill the whole way through.
I also included the base model that I split in creation of the .3mf
The author marked this model as their own original creation.