Limestone sandstone or Ytong in house construction - how to decide?

Hello dear forum,

our planning is now in the final stretch. Now it's about choosing the stones. We are building a city villa with an attached bungalow. The plot is located on a tram track (with a narrow 30 km/h zone street in between), behind it there is a relatively busy road, and a new school center is currently being built (as the crow flies 200 meters).

The options are:
1. Ytong PP2 u=0.23 W/m²K or
2. Sand-lime brick 17.5 with 1600 mm mineral ETICS

The financial difference between the two systems is not decisive. I also know that there are strong opinions here about which system is the best.

I am rather concerned about the sound insulation. I would already classify myself as sensitive to noise and am afraid that if I choose Ytong, I might regret it.
Are there any experiences here? Decisions that were right? Decisions that were wrong? Or decisions that guide me, in whichever direction? The decision for a stone will be a joint one, but I’m probably the only one who tends to sand-lime brick because of the sound insulation.

Thank you very much!
Anna

The options are:
1. Ytong PP2 u=0.23 W/m²K or
2. Sand-lime brick 17.5 with 1600 mm mineral ETICS

What wall thickness does the Ytong have? Maybe you could lose a few square meters there. It could possibly be factored into the decision.
We build with aerated concrete and separate, for example, the granny flat with sand-lime brick.

Oh, Ytong has 36.5. The partition wall between apartments is, as far as I remember, made of 24 sand-lime brick. I am not so much concerned about sound from the other apartment, but rather towards the street. Best regards

The property is located on a tram track (with a narrow 30 km/h zone street in between), behind which there is a relatively busy road, and a new school center is currently being built (200 meters as the crow flies).

Then you should already dissipate the noise before it hits the wall, and the difference between KS and aerated concrete (which, in my opinion, is exaggerated anyway) occurs relatively after the decimal point.