Why was not making up missed prayers mentioned in the Quran or Sunnah, and how did making up missed prayers come about, considering that if a Muslim does not make up their obligatory duties in this life, they will make them up or be punished for them in the Hereafter?

The issue of making up prayers intentionally missed is a matter of scholarly disagreement. The most important pieces of evidence cited by those who affirm the obligation of making them up are: the command for the sleeping person and the forgetful person to make up the prayer, thus the one who intentionally missed it is even more obliged; and that prayer is a debt owed by an individual. This view is held by the majority of scholars, and it is the most cautious and absolving for one's conscience.