This is a hook which allows a generic suction cup to be slotted into it and hung from smooth surfaces.

This uses .8 inch clear suction cups such as: https://www.amazon.com/dp/B0BBTDSNGX?ref=ppx_yo2ov_dt_b_product_details&th=1 for the attachment.

I printed with PETG and used 15% infill with 3 walls. this should be plenty strong for the size of the hook.