What should I do about feeling deficient despite my commitment to acts of worship, and my fear of the impact of the sin of smoking, which I cannot quit, on Allah's رضا (pleasure/contentment)?

To quit smoking, which is a bad, harmful, and forbidden habit, your intention must be sincere and your resolve strong. Sense its harm and evil consequences in this world and the hereafter. Seek Allah Almighty's help through abundant supplication and by observing His obligations, especially the five daily prayers at their prescribed times and with the congregation, for prayer prohibits immorality and wrongdoing.