ETICS with concrete construction or exposed concrete?

first of all thanks for the compliments we really like this design (it was the 2nd one - with small changes compared to the 1st .... here there was a balcony instead of the terrace which was not suitable for us) very much and it hits our requirements right on the head. We initially commissioned a different architect with a design - what came out of it was more than questionable for us - so we immediately ended the collaboration.
The systems from Dennert Massivhaus - I looked into it but can't quite imagine what it will ultimately look like on the outside since most show houses are plastered
What I also wonder is whether an architect is necessary in phases 1-8 for such a building?
I just did some more research and came across a possibly interesting solution - opinions here would interest me.
Please google "baunetzwissen cr-1-f7" then go to images and the first image top left. Looks excellent to me and comes from REC-Bauelemente Berlin. Here there are basically concrete panels with thicknesses from 15 mm - that would mean I could build a monolithic building with brick and use these panels as "cladding". The question here is also the cost? Although I think they will be relatively high. One would have to offset costs for plaster and co. The advantage would also possibly be a different design (color and texture) inside vs. outside.

On the topic of sandwich construction: If thin walls are prefabricated here - how thick would the entire structure then be? Biologically probably one of the safest options since concrete and insulation are on the inside. The variant with "lost formwork" and the required exterior insulation has the disadvantage again that I have to stick something "hollow" on the outside (ETICS). Or am I missing something here?

We initially commissioned a different architect with a design – what came out of it was more than questionable for us – so we immediately ended the collaboration.

If you need inspiration for details again: in the oeuvre of Valerio Olgiati (or his late father Rudolf, who built in a somewhat more organic style) you should find quite a bit.

The systems from Dennert Massivhaus – I took a look at it but can’t quite imagine how it will ultimately look on the outside since most model houses are in plaster

I haven’t seen them live yet, but they have their plant in Bavaria – maybe you can visit them there sometime.

What I also wonder is whether an architect is needed in phases 1-8 for such a construction?

A construction starts with the preliminary design and requires site supervision. Which course of this menu do you think you can omit, or would you boldly like to try your own luck?

I just did some more research and came across a possibly interesting solution – I’d be interested in opinions here.

I had already suggested something similar to you; now you are warming up to it in a different form, as panels/"wall tiles". That does not change my opinion: I consider it a good alternative.

REC building elements Berlin. They have concrete panels starting at 15 mm thickness – for me that would mean I could build a monolithic structure with brick and use these panels as "cladding." The question is also the cost here? Although I assume it will be relatively high. You would have to offset costs for plaster and co. The advantage might also be a different design (color and texture) inside vs. outside.

I would prefer, the closer materials follow each other, to choose similar material categories. Between these concrete wall panels, I would therefore rather put aerated concrete. Bricks might emotionally feel more like "material from biological cultivation" to you – you can expect climatic "cooperation" from bricks at most behind plaster (in my opinion actually only behind clay plaster), but hardly enclosed in a "Castor container" made of concrete panels. That would then truly be only a cosmetic "organic label".

Regarding sandwich construction: If thin walls are prefabricated here – how thick will the entire assembly be then? [...] The variant with "lost formwork" and required external insulation again has the disadvantage that I have to stick something "hollow" on the outside (ETICS). Or am I mistaken here?

I’ll explain it again very slowly: with a wall made of "cast-in-place concrete" you need formwork made of "wooden panels," between which the concrete is poured. This formwork is then removed, so it is not part of the wall, and can be reused.

In a variant of the sandwich concrete wall, this "formwork" consists of concrete panels, which afterwards become the surface on both sides and part of the wall, hence the name "lost formwork." They are thicker than formwork boards, each of the two panels about as thick as a wall in a precast concrete garage. You have to fill them with an on-site "poured" concrete core because alone they would not be sufficiently load-bearing.

However, then you have thermally a concrete wall, which requires insulation that is applied on the outside and plastered (or clad). The inside can remain exposed concrete.

If you fill a similar construction not with concrete but with an insulation layer, then you have no load-bearing core in the middle. Therefore, one of the prefabricated concrete panels (the inner one) must assume this function itself (and be correspondingly thicker). The total thickness does not differ, only the location of the insulation layer (which may be a different material inside than if arranged outside).

The overall weight actually does not change depending on which of these two (among others) variants you choose. But actually, yes: if a thin and a thick concrete panel are prefabricated, then this element to be transported naturally weighs more than if you prefabricate two thin concrete panels and pour the heavy middle concrete layer on site. This means smaller maximum sizes of the wall panels for transport as well as for handling in the factory. To make an example with numbers: where a 12 m long wall panel of the "lost formwork" variant can still be made in one piece, with the "heavier" variant you have to manufacture it "distributed" over two elements.

I would expect the total thickness to be within the normal range, i.e., about between 35 and 42 cm.