Is it permissible to increase the number of rak'ahs in Qiyam al-Layl and Tahajjud, and to suffice with two rak'ahs of Tahajjud and its witr, then twenty rak'ahs of Qiyam and its witr, knowing that she has promised Allah Almighty never to abandon Tarawih prayer unless absolutely necessary?

There is no harm in performing the night vigil (Qiyam al-Layl) with Tahajjud, which is prayer after sleep. However, it is not permissible to repeat Witr in a single night, based on the Prophet's (peace be upon him) saying: "There are no two Witr prayers in one night." The Sunnah is to make Witr the last prayer of the night. There is no harm in exceeding eleven rak'ahs in Qiyam al-Layl, as the Companions used to pray twenty rak'ahs. However, it is not correct to pray Witr and then pray twenty rak'ahs after it; rather, Witr should be the last prayer.