What are sliding cabinets, what are folding cabinets? Do you mean drawers and (normal) cabinets? What does partially mean here?
How do you find the basic layout from the planning perspective?
It's not mine with the attached island, but that doesn't matter.
You don't see much! You can see that there is no space for the side-by-side fridge now because the right side of the plan is longer.
You don't know where the stove will go, where which electrical appliance is.
You also don't know the widths of the drawers or how they arrange with the cabinets.
But that is what matters. Also, the interior makes up a large part of the price. I assume that many cabinets don't have any interior fittings and only the explicitly mentioned carousel is included?
Do you find the offer fair?
If there is nothing inside, it is probably a normal price.
I would sketch the individual cabinets into a kitchen-compliant grid (larger scale, boxes for 10 or 20 cm) and specify the use of the individual cabinets and drawers.