Under-sink cabinet

...in the end, just a bathroom and not the wellness centre of an Italian villa with a view of the olive and lemon trees.

Our guest toilet now welcomes you via motion detector and supports your "business" with Australian bird songs. I think that comes pretty close to the Italian villa. Or something like that. :D

probably a kookaburra, noisy birds

Thank you very much for your answers :)

I bought these construction panels at the hardware store; they come in various thicknesses. I built a shelf out of them (it only needs to be glued, and cutting the panels is easy) and inset a sink. Of course, you can also build the panel deeper and place the sink on top. The whole thing was then tiled. I will probably do the same in the new house. This way, you can implement your own wishes precisely for little money. The whole thing is also suitable for damp rooms, so it does not swell, warp, etc. The only disadvantage (if that is a disadvantage for someone) is that you don’t have doors or drawers. But for us, there are only towels in there anyway, and they are better stored in an open shelf (for us).

I got it from the kitchen builder for 1800,- including installation.

That might be too expensive for the (one or other) OP. His question at least does not exactly target this price range. In my opinion, this question would then be unnecessary. But by now I also no longer understand the OP's problem.

It's not about the price, but about the ratio! And I find the savings of more than half compared to the sanitary dealer quite remarkable. That's why my tip is with the kitchen builder.