Their foot steps sound like they just have 2 pegs for feet… they hit so hard.
And they frequently, almost daily, spend the entire evening stomping around the entire footprint of their apartment.
Are there people who really just get the top floor, and think “I’m so smart, and everyone else can get fucked” then proceed to make all the fucking noise in the world?
Go and have a chat with them. Perhaps as a half joke buy them a really nice pair of slippers for Christmas.
As an aside, I did once share an upstairs flat with a woman who had a prosthetic leg. We had wooden floors. The people downstairs were not amused, though she tried to move around as quietly as possible