Interior wall: aerated concrete or lightweight construction?

make it out of stone. when the tenant screws his TV to the wall, he doesn't think, he just does it. surely it works with drywall too, but not with the hardware store plugs.

That is probably the most fitting argument for a solid construction! When the tenant moves out and removes his plugs, he has to patch a 1.5..2cm hole in drywall. Usually, he does it rather carelessly and even if it is painted over, it stands out. You can see it with a smaller plug too, but a 6..8mm hole is much less noticeable.

Since I also just moved out of a rental apartment, I speak from experience. Also with the "careless"

Whether one can really speak of "solid construction" with 11.5cm aerated concrete is questionable. The sound insulation value of the stone is based on its physics and cannot really be influenced; the drywall can be constructed accordingly if higher requirements exist. Double drywalling on both sides, filling with 40mm mineral wool. Just google the sound insulation values of the corresponding assemblies, you will be amazed.

However, the tenant's argument regarding the destruction cannot be dismissed.
A thinner wall construction, on the other hand, leads to more chargeable living space = higher cold rent. Hmmmn

I can recommend sand-lime bricks. They have the non-load-bearing walls in 115mm thickness and I can say the acoustics are brilliant. Also perfect for hanging heavier things.