Is it permissible to listen to a Sheikh's recitation from a recorder and repeat after him from the Mushaf with the intention of completing the Quran in Ramadan due to frequent waswasa (whispers/obsessive thoughts) and errors in recitation, and will one receive the full reward for completing the Quran thereby?

If one reads the Qur’an aloud behind the reciter until completion, their ختمة (completion) is considered valid. However, it is better to use a Mushaf with a teacher for listening, then to read after the reciter has paused. As for reading simultaneously with the reciter, this goes against the words of Allah Almighty: "And when the Qur’an is recited, then listen to it and pay attention that you may receive mercy." Allah also forbade His Prophet from reading along with Jibreel, saying: "Move not your tongue with it, [O Muhammad], to hasten with it."