Use a block mural to place a built-in bath with a panel beneath (and light).

Place a built-in bathtub and use the sanitary mural function to finish the built-in. Or do it yourself: place a block mural and use the Cut Out Filling function.

Set the mounting height of the bath at 15 cm, so there is empty space underneath the mural.

Use wall view to place and edit a new block (menu Room | Mural).  Select all the objects and make it a group (CTRL+G). Now you can tile the mural, place a light, e.g.