More questions ... kitchen installation with a foreign/worktop

Hello,

I am diligently working on the kitchen planner and designing my kitchen. The goal is to have it delivered and assembled.

Now my question: I would like to use a countertop not from Ikea. I will have the cutouts for the ceramic hob and sink made. When the kitchen is delivered and assembled, am I correct in assuming that the assembly subcontractor will not install the ceramic hob and sink into the countertop nor attach the countertop, since the countertop does not come from Ikea? At least I think I read somewhere that this is how it works with "non-Ikea" devices (for example, they would also not install a ceramic hob from XY into the Ikea countertop)?

Surely people have already chosen a different countertop and had it assembled. How does that work practically? The carcasses are assembled, and the rest remains lying around? Including the water connection?

Best regards, Tina

In Austria, of course, non-IKEA devices are also installed... however, at a slightly higher price. In addition, for warranty reasons, only new devices are installed.

But unfortunately, I do not know if it is different in Germany.

Regards