Will God make me undutiful to my parents as a punishment for their undutifulness to their parents, and will my children also be undutiful to me, and what can I do to avoid that?

The parents should be advised to repent for their disobedience towards their own parents, and to mend their relationship with them if they are still alive. Otherwise, they should frequently seek repentance and pray for them, and execute their will, based on the hadith: "Is there anything left of my duty to my parents that I can do for them after their death?" He (the Prophet) said: "Yes: praying for them, seeking forgiveness for them, fulfilling their promises after them, maintaining the ties of kinship that are only maintained through them, and honoring their friends." As for the questioner, he is not held accountable for his parents' disobedience. He should strive to be dutiful and obedient to them in what is good, ask Allah for help, and not let himself be preoccupied with destiny.