If ecological, then above all sustainable
stone on stone simply lasts longer than wood, in magazines or various unsubstantiated online sources it is mentioned, to my knowledge, 80 years for wood vs. over 100 years for stone.
In my experience, houses with a timber frame construction are anything but cheaper than solid houses, especially not if you apply exactly the same features.
In general, but especially when ecological building is important, in my opinion insulation made of Styrofoam or similar products is absolutely out of the question. Contrary to the manufacturer's claims, it is indeed flammable (hopefully never as bad as the house fire in England in recent days) and according to many opinions I have heard and read so far, this is from the outset special waste that does not last 80 years, but more or less rots beforehand(?).
For me, only mineral wool or monolithic construction come into question here. Mineral wool is available with a stabilized outer surface to be plastered, or a double masonry wall is necessary (e.g., clinker facade, does not have to be repainted = even better ecologically).
My tip: ask many construction companies and architects and get everything on a fixed-price basis and all with the same features (check what additional costs are for certain features that other providers have included in the price).