Well-designed product, but if the tile has the slightest inconsistency/texture or if the suction cup touches a joint (note that the suction cup is large in diameter, so it requires a large surface area, so it will not fit if you have small mosaic tiles, for example), then it cannot stick securely and becomes dangerous and essentially unusable.
We decided to glue the suction cup with glue and it applied perfectly (it was and still is the only solution I can suggest to you). Even inside the bathtub where it gets constantly wet.
To avoid the above, you can purchase a handle with screws.