Very little, and rarely, if I understand correctly. The characteristic thwop-thwop noise of many helicopters is from the blade passing through the vortex created by the previous blade. In some circumstances, this might lead to local and intermittent supersonic flow, but it's not typical. I think it also only happens when the vehicle is moving in a particular way, but I don't know how vortices propagate from a rotor blade, so I couldn't say how or when the supersonic flow is most likely to occur.

I should have said explicitly, rather the subsuming it in all else being equal, that it’s _very_ different between ‘multicopter’ mode and flying under a wing. The later is, of course, much mor efficient, and the propulsion is correspondingly much quieter.

EASA released regulation, and despite whatever companies want you make believe, Airbus being none of those, these aircraft are not allowed to land on a supermarket parking to fly you home. The operate from yet to be defined and built Vertiports (also airports and heliports and pads), for which the basic regulation is there.

Think helipads and not speeders on Coruscant.

Sure, but then the engines are off. And some cones and such are placed to prevent people from stumbling into the blades.

Electric engines can be stopped and started quickly and reliably, so they don't need to run while passengers are entered or exiting. This makes the vehicle much quieter and saves battery.