Construction costs are currently skyrocketing

I still remember how the salesperson explained the offer to us and, regarding the surcharge for a certain construction system, said "so that we don’t have rubbish stuck on the walls." Unlike [WDVS] in the standard, I can’t interpret it any other way ;)

Are there only general contractor companies here that build with 24 cm bricks and external thermal insulation composite systems (ETICS)... Why, dear God

Are there GU companies here that only build with 24 cm bricks with ETICS... Why does dear God know

Why? From your experience, what speaks against it?

Are there GU companies here who only build 24 cm bricks with EIFS... Why, dear God, why

Results in the thinnest possible exterior walls. You effectively sell a few more square meters of living space with the same volume.

If [WDVS], then also consistently with the thinnest possible wall behind it (isn't even 17 cm sand-lime brick sufficient?). Otherwise, you combine the disadvantages of both systems.

If using ETICS, then also consistently with the thinnest possible wall behind it (isn't 17 cm calcium silicate brick sufficient?). Otherwise, you combine the disadvantages of both systems.

I have exterior walls made of 17.5 cm calcium silicate brick (also calcium silicate brick on the inside) and 20 cm mineral wool.
What mistake did I make in the selection of building materials?
Please share answers based on your own experience.