So after one year having this in operation, it seems to last just fine so here we go:
print the "WheelHubRepair" piece, PLA should work fine
you need two self tapping screws , length about 25-30mm in length, 3mm diameter. And a method to cut some aluminum or steel plate of 5mm thickness precisely.
you need to modify the robot wheel:
then you need to cut two pieces of metal (steel, aluminum) and make them fit snug into the two printed wheel hub repair part:
mount the printed repair piece on the wheel, tighten the screws.
Put the wheel back on the mower, check if everything fits.
The author marked this model as their own original creation.