Why is God not incapable, and what is the solution to the doubts that prevent me from worshipping and memorizing the Qur’an, and am I therefore considered a doubter and deserving of the Fire?

The best cure for satanic whispers (waswas) is to seek refuge with Allah from them and to turn away from them. If they are mere fleeting whispers, repel them by ignoring them. However, if a doubt (shubha) becomes entrenched, it requires examination and reasoning to refute it.

Refuting doubts is as follows: - The devil's statement: "Other lords do not know of our existence." This negates their divinity, because the Lord's knowledge encompasses everything. - His statement: "Perhaps Allah does not know about these creatures." The answer to this is that Allah encompasses all things in knowledge. And if there were lords other than Allah, strife and corruption would certainly have occurred in the universe, as confirmed by His saying, the Almighty: "Had there been within them gods other than Allah, they both would have been ruined." - If the whispers are merely fleeting thoughts that have not settled in your mind, they do not harm you, and your faith is sound. But if they settle in your heart, then they are doubt (shakk), and doubt in Allah's singularity in Lordship or Divinity is major disbelief (kufr akbar) that expels one from the fold of Islam.

The advice is to cease these whispers and to seek refuge with Allah from Satan.