ᐅ Exterior wall construction material selection: aerated concrete, fiber insulation boards, mortar joints, and facing bricks (cladding)

Hello everyone,

We are currently planning our "urban villa" and have received the first offers. The masonry company proposed the following wall construction:

17.5 cm aerated concrete, 16 cm fiber insulation boards, 2 cm gap, and facing brick = 47 cm wall thickness.

At the same time, they mentioned a 30% higher cost estimate for masonry work if we choose sand-lime brick.

The construction would then likely be:
17.5 cm sand-lime brick, 20 cm fiber insulation, 2 cm gap, and facing brick = 51 cm wall thickness.

We are absolutely unable to decide between aerated concrete or sand-lime brick, excluding the additional costs.

Which option is "better" and more sensible?
We can’t really judge whether climate performance or sound insulation is more important, since we are currently living in an apartment with sloped ceilings.
Therefore, we don’t have experience with either and are looking for advice.
What do the experts or people familiar with both say?

Best regards