Can Fatwa No. 98119 be applied to all types of acts of worship, such as congregational prayer and reciting the Qur'an, such that performing the act of worship is sufficient to earn reward, or is the fatwa specific only to supererogatory fasting?

What was read in the fatwa (definition) is not specific to fasting; rather, it includes every act of worship. If you perform an act of worship as required, you will receive the full reward. However, if you combine more than one intention in a single act of worship, this brings a greater reward, such as praying in the mosque with the intention of gaining its reward, increasing the congregation of Muslims, and maintaining the houses of Allah. Imam An-Nawawi said: "If he intends to have marital relations with his wife, he aims to fulfill her right, obtain righteous offspring, and safeguard his chastity… Whoever is deprived of intention is deprived of a great good." The evidence for this principle is: "Indeed, actions are by intentions." Sheikh Ar-Ruhaili mentioned that intention is characterized by the multiplicity of objectives; a doer can intend multiple things with one action. If they are good, his reward increases, and if they are mixed, he receives a share of good and evil accordingly.