Indoor soundproofing: Drywall vs. Solid construction

Weight is only one aspect of sound insulation. More important are different layers, consistent decoupling, and avoidance of sound bridges. For example, a double-planked metal stud with wood fiber insulation can then insulate better than a solid wall.

I can already tell, it's not simply A or B :)

By the way, I'm primarily concerned with typical living room noises: adults watching TV or sitting together with several friends, child sleeping. So rather mid/high frequencies than something bassy. Moving furniture rather not.

What do you say about the screed separation? For the above-mentioned noises, is it rather unimportant or does airborne sound also go into the screed and get transmitted as structure-borne sound?

In our bungalow, the screed is decoupled in every room,
partition walls KS,
actually heavenly quiet,
except for a film at very loud volume, you can hear it everywhere.
So Dolby and children should be separated by more than one wall