Poroton or Ytong - insulation values, etc.?

Hello,

.... sand-lime brick is thus off the table!

Are you an expert? Probably not, since this is a very superficial assessment! Best regards

...
Otherwise: If it is not supposed to be a passive house, exterior walls made of KS will probably also work - and everyone is happy.

Why should that be a problem with KS?

Regards
Peter

What did it end up being?
I am now facing the same question: 17.5 cm aerated concrete or Poroton in combination with mineral fiber insulation and cladding.
How big is the difference in terms of soundproofing?