What is the way to get rid of doubts and whisperings that attack the heart and raise suspicions about one's creed, making a person question their faith, especially when they try to draw closer to Allah and seek religious knowledge?

These whispers are from the wiles of Satan, through which he seeks to corrupt your heart and distance you from obedience to your Lord. Therefore, you must strive against them. Whenever Satan casts any of these whispers into your heart, cease thinking about them and turn away from them. Instead, think about what benefits you in this world and the Hereafter. Seek refuge with Allah from the accursed Satan, and strive diligently in supplication for Allah to remove these whispers you are experiencing. Know that these whispers do not harm you as long as you dislike them, and you are upon Islam, praise be to Allah. Rather, you are upon goodness as long as you are striving against these whispers, and you are hopeful for reward and recompense from Allah the Almighty.