Printed from PET-G with 3perimeters and 40% gyroid fill works fine.
The “outside” part contains integrated support (blue part in model image). Remove the support when printed.
Check how the part (especially bridge at 10.7 mm layer) is sliced, the bridge should be across the object (see images).
To modify the model use the source in “kinder CAD”
The author marked this model as their own original creation.