In my OC (I’m on the committee) we’ve had similar issues. An Acoustic Engineer has recommend fitting external door seals such as Raven seal RP94Si. This seal should be fitted to the top and sides of the outside (the lobby side) of the apartment entrance door. Door bottoms can also be fitted with a drop seal such as Raven RP 99si.
The seal would mean that the inward opening doors close a bit like how a refrigerator door closes. One owner has already fitted such a seal (without OC permission) and reports that it made a big improvement.
We are in the process of getting the seals fitted (at OC expense) to all the other apartment entrance doors.