This may or may not be instructive.
I used to live on the top floor of a tower block with less than soundproof walls and floors.
A couple moved in downstairs from me who were a complete nightmare. When they weren't having screaming arguments, they were having late-hours post-pub parties against which it was impossible to get to sleep. Even knocking on their door to "interact" with them bought nobody to the door, except to look through the peephole at me.
So. Once I had the opprotunity to go away for a long weekend (MTBing in Wales. Ha!) and formulated a plan.
I plugged in a portable radio in the room directly above their bedroom. As I left, I switched it on and turned it up to maximum volume.
When I got back on the Tuesday, I switched it off.
Never had another peep out of them…
😉