Is sound insulation according to DIN 4109-1 sufficient for a mid-terrace house?

Already opinions that refute my concern.

Oh yes, just for comparison. In normal apartment building construction, the apartments are not separated by separate walls, but the walls are shared. And even there - as exceptions always prove the rule - it is already relatively livable. And you have concrete walls with a lot of mass and separating joint panels in between. Every tenant in a multi-family house would probably be insanely jealous of you.

I think there was shoddy work done during construction at our place. I guess it's the classic mortar blob between the walls. You can also feel the structure-borne noise on your own body. But as already noted, compared to an apartment it is quite luxurious. It doesn't really affect much.

Partition walls between terraced house party walls = reinforced concrete walls, thickness 12 cm each. Between the walls, partition joint plates, thickness 4 cm.

The description does not sound to me like a terraced house according to the current standard for terraced houses, but rather like a condominium in terraced house form according to the standard of a provider like "Deutsche Reihenhaus" and similar (which, in my opinion, are clearly offers for people who explicitly like such concepts, but not for everyone else). If I am correct, you will have much bigger problems with other points than with the sound insulation DIN.

The layout in our terraced house is quite similar. Currently, both our neighbors are working and doing interior finishing - we hardly hear it at all, unless someone bangs directly on the concrete wall next door. We don't hear normal conversations etc.

á la "Deutsche Reihenhaus"

Whereas that is still a highly professional provider who offers little reason for complaint - a neatly finished product for a tight budget.

Our series is not a WEG.
Real partition.

Are RHs built differently in WEGs, meaning with worse soundproofing?
Hardly, right?