Must I repeat the prayer I led due to feelings of showing off (riya') and obsessive thoughts (waswasa), knowing that I supplicated to Allah during prostration with the dua: "O Allah, I seek refuge in You from associating anything with You while I know"?

These are whisperings from Satan to disrupt your worship and bring you grief and sorrow. The only cure for them is to ignore them and seek refuge in Allah. It is important not to pay attention to what Satan whispers about repeating prayers, because responding to whisperings opens a door that is difficult to close.

Ibn Taymiyyah said: "Whisperings (waswas) afflict those who turn to Allah. The servant must remain steadfast, be patient, and consistently engage in dhikr (remembrance of Allah) and prayer, for Satan is like a highway robber."

Ibn Hajar al-Haytami said: "The cure for waswasah (whispering) is to completely ignore it. Whoever does not pay attention to it will find it quickly disappear, and whoever listens to it will find it increase until it drives him to the point of madness. What supports this is what came in the Two Sahihs (Bukhari and Muslim) that whoever is afflicted with waswasah should seek refuge in Allah and desist."