A first step seems to be put down conventional foam rubber rug padding and rug. You could take it with you if you move , and it adds some decorating options. It won't stop noise coming up the walls but will tend to absorb sound from any source. If budget permits ,drapes also absorb some sound.
There are two kinds of “sound control” problems: 1) airborne sounds, and 2) impact sounds.
Airborne sounds (talking, tv, etc.). When I first read your statement, I thought this was your problem because it occurs BELOW your unit. As soon as that noise travels in the air up to your apartment, it becomes “airborne sound”.
However, now I think it is an “impact ...
I’m American so I don’t know anything about metric, but I’ll try.
The “Tables” you refer to have footnotes that are not available. I’ll assume the footnotes qualify the loading, etc. Because the Tables indicate “Maximum Spans for Floor Joists” I’ll assume they’ve added a dead load factor and live load factor.
I don’t know why you’d want to use “Northern ...