What is the ruling on repeating the Basmalah during ablution and the accompanying thoughts during the intention for prayer? Is the intention considered valid in this case? What are the consequences of errors in pronouncing the letters of the Isti'adhah and the Basmalah? And are the whispers of the soul that sometimes come with intention among those that Allah has overlooked?

You are afflicted with a high degree of waswas (obsessive whispering), so you must turn away from it and not give in to it. The person afflicted with waswas has a special ruling, and hardship is removed from him. The matter of intention is easy. Sheikh al-Islam Ibn Taymiyyah considered the intent to perform an action as a necessary matter within the self. As for the tasmiyah (utterance of "Bismillah") that is in the heart, it does not require moving the tongue.