Shower basket holder

I designed a holder for a shower basket like this https://www.xxxlutz.de/p/smedbo-duschkorb-001311003209
The vertical bar has to be a diameter of 5.0 mm

I use some 40mm suction cups https://www.aliexpress.com/item/1005006008591027.html?spm=a2g0o.order_list.order_list_main.41.38501802Hw9A5Y
The top part of the suction cup has a diameter of 8.5 mm.