Integrate fresh air supply for Bora exhaust system into the kitchen block

What does the energy consultant say about the solution? We are not making the houses more airtight and insulating them better for nothing. A ventilation concept without heat recovery somehow doesn't fit with the rest of the concept, does it?

.. so you are a SUPPLY AIR user. And then you ventilate moisture through the window after cooking or while cooking or more slowly through the controlled residential ventilation. And in contrast, there are EXHAUST AIR users who want the moist air to go outside immediately.

Apart from the fact that with the currently very dry air we are grateful for even the smallest contribution to humidity: we also have an open floor - we have never had to ventilate because of "cooking". Ok, I once let a schnitzel get a bit too "well done" in December, but that doesn’t count. I therefore still consider such an elaborate solution to be completely exaggerated.

I still consider such a complex solution completely exaggerated.

The solution is not that complex if it is planned during the construction phase. You also save money on carbon filters in the future, which you only need with recirculation.

... one thing you have to be clear about is that odors do not only occur during cooking, but continue when the food is brought to the table, etc.

Regarding the distribution of the supply air, if your duct runs in the floor up to the island, the air will not get warmer either.

One supply air point is enough, from which the air is perhaps distributed to the right and left with a Y-piece. Or at one end of the row of windows and then a right angle so that the air takes the path under the kitchen cabinets. But your kitchen consultant should also be able to give you tips here.

The shadow gap with baseboard ... in case of doubt, simply make the baseboard half a centimeter shorter. Alternatively, indeed ventilation grilles, e.g., in the area opposite the island where it is not visible from a distance. Here too, I recommend your kitchen studio. Or try googling for further answers.

Is a controlled residential ventilation system also planned?
Then your chimney sweep will tell you what else you need.
We have a chimney ourselves (not yet in operation, possibly never), an exhaust hood (basement through the floor slab and a backdraft damper outside), and controlled residential ventilation.
According to the chimney sweep, this combination of three (chimney/controlled residential ventilation/exhaust hood) requires a differential pressure monitor.