Does one who renews his Islam due to obsessive doubt and suspicions become an unbeliever, and is he held accountable for this action, and what is the ruling on renewing Islam without a reason?

Renewing one's Islam by uttering the word of Tawhid (Oneness of God) is a righteous deed that does no harm; rather, it benefits its doer. It is stated in the Hadith: "Renew your faith. It was asked: O Messenger of Allah, how do we renew our faith? He said: Increase in saying: 'La ilaha illa Allah' (There is no god but Allah)." One must strive against their self to get rid of these whispers and turn away from them, for a Muslim does not abandon their religion merely by these whispers.