Sound insulation of prefab house attic

Hello,
I have been thinking about additionally insulating my attic against sound with rock wool. My attic consists of mineral wool, vapor barrier foil, and plasterboard. Would it be possible to lay a layer of rock wool on top of the existing mineral wool and screw wooden boards over it to make the whole thing more compact? Would that help? Pictures are attached.
Regards, Theo

what requirements should the soundproofing meet? Should a band play upstairs and you can't hear anything downstairs anymore, or is it only about a certain reduction of footsteps?

what requirements should the soundproofing meet? Should a band be playing upstairs and you hear nothing downstairs, or is it just about reducing footstep noise?

Hello, outside noises should be somewhat dampened.

What are the outside noises? Environment or airplanes?

In the end, it still comes down to two decisions.

Do I get professional help with measurement of the disturbing noises and an expert opinion on how to fix it, or do you haul wood, wool, drywall, whatever up there and screw it to the floor to then feel somewhat quieter...

What are the outside noises? Environment or airplanes?

A mixture of both. Airplane noise but less.

see above. I just changed my post as you replied... Sound is tricky... it can also come out in the measurement that the sound is transmitted through the facade, not from the roof