Is it considered sound doctrine for moments of joy and love for Allah to outweigh moments of fear of Him, and is it permissible to respond silently to the Qur'an while the Imam is reciting?

The worship of Allah is not complete except with love, fear, and hope. Reverence can be attained by frequently reading books on encouragement and discouragement, contemplating the texts of promise and warning, and asking Allah for reverence. Your interaction with the verses, your belief in them, and your submission to them are permissible. Fear should not be limited to the time of recitation but should accompany acts of worship and supplication, while being mindful of Allah's saying: "Inform My servants that it is I who am the Forgiving, the Merciful. And that My punishment is the painful punishment." One should be in a state of anticipation, fear, and hope in Allah, for fear and hope are like two wings of a bird. It is recommended for fear to be greater during health, and hope to be greater during illness and when approaching death. The predominance of fear is more beneficial for most people, provided it does not lead to despair. However, at the time of death, the predominance of hope and good expectation of Allah is more beneficial.