The slats in our shower caddy often let soap fall through; this insert was designed to fit a couple of bars of soap, with smaller drainage gaps.

To make it work on a countertop, you could attach some rubber bumpers to make it more grippy, and to provide a bit of clearance for the water to drain.

I printed in PLA with slightly accelerated Cura settings on my Ender 3 V2 Neo, using a 0.6mm nozzle. I'd recommend making sure your print speed isn't too high to avoid the gaps I got on some of my walls.

The link to the OnShape model is here, if you'd like to remix it!