Differences of wooden houses

My thinking was partly that a "real" wooden house can only be a Canadian log house

You really don't want to know what wall thicknesses that would mean to be compliant with the Energy Saving Ordinance. Solid wood - moreover, widely traveled - would have little to do with eco-biological sustainability; that's more for people who drive an SUV to the farm shop. Instead of solid wood, "massive wood" is currently increasingly used, harshly compared to "shaped ham," but at least it is more eco-biologically sustainable. Recently, I even read a reference here to beetle wood, which in my opinion is also a fine thing.

after 10 years (that's what I was told, we are not that far yet) to clean the air distribution boxes.

See here: I am not filled with hope, the deposits quietly accumulated in the hub.

Ventilation is always possible. If you don't want to, then build without it.

Our system turns off temporarily during the day in summer so that no warm air is brought into the house. It quickly becomes very stuffy, not warm. One airing through is no longer enough.

Maintenance so far 4-5 times a year cleaning or replacing the filters in the system, changing the cassette twice, cleaning the exhaust filters about every 6 weeks, vacuuming the floor vents twice a year. Pipes are still clean after 2.5 years - as far as one can see. Friends have to clean much less. They live in a new housing development with a dead-end street, we have the main road in front of the house, behind it our private jungle. We are also allowed to clean the gutters 4 times a year.

Instead of solid wood, "solid wood construction" is increasingly being used nowadays

P.S.: However, solid wood construction is built by a minority of (usually small) "prefabricated house builders". The classic "prefab" house is made of wooden frame panels, that is, wall panels whose spaces between the "beams" are filled with insulating materials, whereby in the last two decades a lot has happened especially in terms of building biology regarding the quality of these materials. Seen in this way, you also get a better house compared to ETICS – although compared to monolithic stone construction, rather only slightly more or equally good.

You just need some kind of ventilation.

If you want a ground source heat pump with a horizontal collector, you will probably also want BKA.

So your goal is to use as little energy as possible.

In my opinion, controlled residential ventilation with heat recovery is basically mandatory.

Especially with low consumption, the share of, for example, hot water or ventilation losses in energy consumption rises significantly.

...Instead of solid wood, "solid wood block" is increasingly being used nowadays, loosely comparable to "shaped ham," which is at least more eco-bio-sustainable. Recently I even read a reference here to beetle wood, which in my opinion is also a fine thing. ...

Yesterday I spoke with "our" master carpenter (who will help build our house). He also said that there is currently an increased amount of beetle wood (bark beetle) and that for this reason prices have even dropped. Maybe our roof frame will even be made from it in October.

If you are already doing a brine heat pump and photovoltaic on the roof, why not take the whole step and go for KfW40(+) and plenty of subsidies? The only thing missing is the Controlled Indoor Ventilation that you do not accept so much...

I seem to remember: Everyone who has one does not want to miss it, those who don't have one are skeptical.