Styjun

This is something I always found to be a bit of a contradiction.

The Torah states that a person's sins are their own to bear and that no one may die for the sins of another.

Parents shall not be put to death for children, nor children be put to
death for parents: a person shall be put to death only for his own
crime. - Devarim 24:16

At the same time, we see examples where the Torah cites Hahsem is punishing either entire nations of people or multiple generations of people for a previous wrongdoing.

• The killing of the Egyptian children for the sins of their parents.


• The killing of the Canaanites (including children)


• The killing of the Amalekites (including children)

Cursing multiple generations of those who worship graven images and false gods:

You shall not bow down to them or serve them. For I the LORD your God
am an impassioned God, visiting the guilt of the parents upon the
children, upon the third and upon the fourth generations of those who
reject Me, - Shemot 20:5

Psalms even speaks of it being a blessing to inflict punishments against others in the way they inflicted them upon us.

Fair Babylon, you predator, a blessing on him who repays you in kind
what you have inflicted on us; a blessing on him who seizes your
babies and dashes them against the rocks! - Tehillim 137:8-9

How exactly do we rationalize this with regards to the idea that sins fall upon the individual alone and not their entire community/family/nation?

According to Sanhedrin 27b, children are punished for their fathers’ sins only when they follow in their footsteps; children who do not follow the sins of their fathers are not punished on their account.

ובנים בעון אבות לא והכתיב (שמות לד, ז) פוקד עון אבות על בנים התם כשאוחזין מעשה אבותיהן בידיהן

Are children not punished for their fathers’ sins? But it is written: He remembers the sins of the fathers on the children! That is when they grab hold of the actions of their fathers in their hands.

In all of the examples you brought, the children were just as guilty as the fathers.

Further, Sifri Devarim 280 understands that minors can be punished for their fathers’ sins:

איש בחטאו יומתו. גדולים מתים בעון עצמם, קטנים מתים בעון אבותם.

”Each man for his sin will they die” - Majors die for their own sins, minors die for their fathers’ sins.

1. Your first quote is only relevant for a Beis Din, for Earthy punishments. One can not offer himself to be stoned instead of his son that sinned, for example.



2. 
   

   Traditionally (source needed) the souls are reincarnations of previous souls, bearing their deeds and judgments. Similarly to the 9-dots-4 lines puzzle, as we are unable to solve the justice/injustice paradox within this world (for example why little kids suffer terrible illnesses and death), we have to assume that both souls and judgments extend to the pre-after-world.

   
   
   

   Therefore G-d allows himself to judge single people, nations and generations by being able to see the big picture extending the limits of this world.