With how many yoyos are out there, and considering the limitations of yoyo design, yoyos are inevitably going to look like each other. No one is copying anyone, it’s just how it is. No point in fussing about it.
I call it the hour-glass shape. Thats like patenting anything thats a square shape, you can’t. A square could be a toy for a child to learn shapes, or a weapon of destruction.