What are the experiences with recirculating range hoods in new constructions meeting KFW40 standards?

Ablauf

Exhaust air.

Of course you smell the food for a while, although I don't always understand that people want to get rid of the smell of good food quickly and completely;

I never understood that either. Delicious food is allowed to smell.

Fat clouds hanging in the air like at a fries stand should rather be eradicated in today's show kitchens.

Although we don't have a show kitchen, it's open, and I have no grease film in the place, although we also often don't turn on the recirculation air.

No offense. But a 500€ hood is nothing more than a fan compared to Berbel, Gaggenau, Novy, Bora, etc.

I took exactly what I needed and with which I am satisfied. A "dick measuring contest" doesn't help me much; there is always more, better, greater. I was talking about our solution, which works wonderfully for us, nothing more but also not a bit less.
A thread lives precisely from different perspectives, and a TE can then see if it helps them.

Then you don't even know any "really" well-functioning recirculation hoods.

Fortunately, there are many things I don't know, and yet I don't lack anything.

Fortunately, I don't know a lot of things and yet I don't miss them.

It is also a question of use case. If you regularly fry and occasionally even deep-fry, the cheap convection is not enough. If it’s about other cooking, that can be sufficient. We had cheap convection as "heavy cookers," it wasn't optimal. Sure, it also worked with airing afterward. Now we have exhaust air on a 200mm pipe – galaxies lie in between. And the more expensive convection solutions are then rather comparable to our exhaust air. They solve completely different problems. (I’m writing this because the argument "you don’t miss what you don’t know" is not a good one. If it were, you couldn’t know what you need either...)

We have controlled residential ventilation integrated into the BUS system so that when the stove is used, the ventilation function of the controlled residential ventilation starts for 30 minutes, increasing from 30% power to 70%. This quickly removes the "used" air saturated with odors and replaces it with fresh air.

This is particularly about exchanging possibly humid air ... cooking pasta, etc. With the different price ranges, it often comes down to the appropriate volume, but especially also the noise level. A frequently mentioned argument "I don’t even turn on the range hood because it’s so loud" can become irrelevant with a higher price range. Ideally, you turn the range hood on before the cooking triggers the need for extraction so that a proper draft is established. And, modern hoods have, as well, a post-run time of at least 10 minutes after cooking. This is especially important with recirculation to allow the activated carbon filters to dry after moist cooking sessions with lots of steam.

It is also a question of use case.

I absolutely agree with you; that’s exactly why I described our individual use case. Different user behavior or perception will probably lead to a different solution; I assume nothing else!

"heavy cookers"

completely different use case than ours, also for the kitchen itself

( I write this because the argument "you don’t miss what you don’t know" is not a good one. If it were, you wouldn’t be able to know what you need either... )

Then I may have described that vaguely. I also know other appliances or have looked at them once but we still had this device from the old apartment and are still absolutely satisfied with it; this with the firm knowledge that—as always—it could be better and also more expensive if we wanted. As described, I especially like to use the grill (e.g. today) on the terrace, which certainly is not everyone’s thing. I can understand anyone who prefers it differently.
Maybe I better say: With our individual user behavior and perception, we saw no need for a higher-end system and are satisfied with this recirculation hood.
For us, air conditioning or similar things were mandatory, for someone else that is just frills.
I absolutely do not want to ever tell anyone that ours is better or the only sensible choice; but it is also the other way around. Only the OP can find out how what he has read here applies to his own situation.

Only the OP can find out how what is read here fits their own situation.

Right. And my recommendation is to state the use case. For a steam oven/convection oven kitchen, where nothing is fried and frying is mostly done on the balcony, standard convection is enough. If you sear sharply indoors, fry green herrings for pickling, 3kg of meatballs for buffets, or make large quantities of fried potatoes on a hot griddle (these are really odor-intensive messes for us), you simply need a different solution. And then I recommend exhaust air or very high-quality convection variants. I admit I am a fan of exhaust air: we often have stocks or sauces simmering that release steam for hours.