Install an exhaust fan in the grille. It can be a regular, bathroom one.
It will direct your and your neighbor`s odors in the direction of the ventilation draft.
It is also worth sending the administration, but not to the neighbor, but to the ventilation, to check the patency and clear it if necessary.
Maybe the ventilation is simply blocked and the best way for air to flow is through your apartment.
Jackdaws like to build nests in ventilation ducts. Then the ventilation simply does not work.
In old buildings, pieces of bricks from the casing sometimes block the channels.
You can check the patency yourself, but if the building has a manager, just complain about improper ventilation. After all, this is what he takes money for.