Wa-alaykum as-salamu wa-rahmatullah wa-barakatuh

In the Name of Allah, the All-Merciful, the Mercy-Giving

All praise is due to Allah. Peace and blessings be upon His Messenger Muhammad.

 

“We” does not necessarily indicate plurality. It is widely used by kings and other sovereigns in their speeches to express a sort of magnificence, authority, and supremacy (see Merriam Webster Dictionary, for example). Almighty Allah is the King of all kings and the real Magnificent and this is why this pronoun is used when referring to divine acts and deeds. On the other hand, when referring to the divine entity, only the pronoun “I” is used to indicate the Oneness of the Divine Being.

 

Almighty Allah knows best.