What is the best way to pray Witr for someone who intends to perform Qiyam al-Layl (night vigil prayer)?

The best approach for someone who prayed Tarawih behind an Imam and wishes to pray Tahajjud later in the night is to continue with the Imam. If the Imam prays Witr, this person should intend to pray two rak'ahs, then pray one rak'ah after the Imam finishes, and then pray Witr after their Tahajjud. This way, they combine the virtue of praying Qiyam with the Imam until he leaves, and the virtue of delaying Witr. As for an individual who is confident in their ability to pray Qiyam later in the night, it is better for them to delay Witr. The Shafa' is the prayer that precedes Witr from the night prayer.