Is repeating and reoffering the prayer, due to the obsessive doubt of not completing the bowing (ruku'), even with the certainty of having performed it, necessary, or does it cause undue hardship?

What an inquirer experiences concerning excessive doubt in his prayer is waswasa (whispering from Satan), and its cure is to disregard it. If the waswasa becomes frequent, the worshiper should not pay attention to it or respond to it, unlike a worshiper who is not afflicted by waswasa, who is obligated to perform what he doubted and build upon the lesser number of units. The website is Sunni, affiliated with the Ministry of Endowments and Islamic Affairs in the State of Qatar, and no single mufti issues fatwas individually; rather, they pass through a group of knowledge seekers and reviewers. Dr. Al-Qaradawi has his own separate website.