I have added two small balls inside the toy which makes a rattle sound. This makes it interesting for the cats. Also Cat toy v3 have increased thickness of the sphere from 2mm to 3.2mm. Increased thickness can give more strength compared to cat toy v2.

You can print this in single step and without supports but there is two methods.

EASY METHOD > I have uploaded gcode for ender 3 printer with temperature 205 and speed 50. This has all supports methods with correct orientation. you can download that print with tuning the temperature and other parameters during printing from printer.

EXPERT METHOD > I have used Cura and I can guide you on how to print this object in that. You have install custom support cylinder plugin from market place. Then open 3mf model in it and you make sure that the cone which is at the base and the cylinders connecting the balls are printed as supports. Use Brim typed adhesion. Change wall count to 4 so, which will avoid useless infill in the narrow walls.

Finally you have cut the supports that of the balls to make them free and tumbling inside the shell. Try to cut the base of the small balls so that the balls wont have any support protruding.