I'm quite aware of how soundproofing works. It seems like you and others in this comment section don't though.

Rooms are often soundproofed to make sure sounds don’t get INTO a room.

Oh my god really? I never knew/s

The effectiveness of soundproofing whether it's meant to keep noise in, out, or both is dependent on the materials used and how they are used/where they are placed. For instance OP placing a soundproofing rug down would be less effective than the downstairs neighbour having panels put on their ceiling.

OP has already stated that they have tried the rugs and other methods on their end, so at this point the options are:

A) the neighbour is "inconvinced" for maybe a few hours while the soundproofing materials are put on the ceiling.

B) OP is inonvinced for at least several days while their floor is ripped up and soundproofed (in order to achieve a similar affect)

I'm astonished at not only your ignorance, but your arrogance.