How is the word (found you) in the verse (Did He not find you an orphan and give you refuge) to be interpreted, knowing that Allah Almighty is the Creator of the Messenger, may Allah bless him and grant him peace, and the meaning here is not one of surprise?

The verb "wajada" (found) in the Quran carries meanings unified by the idea of obtaining something valuable that was previously absent. It may signify finding something unexpectedly, without prior knowledge (surprise), as in: (They said, "His recompense is that the one in whose baggage it is found – he himself will be his recompense.") [Yusuf: 75]. It may also mean knowing the existence of something in a certain state or condition, such as: (Then they would not find within themselves any discomfort from what you have decided) [An-Nisa: 65]. This latter meaning (knowledge) is intended when "wajada" is attributed to Allah the Almighty.

In Surat Ad-Duha, the verb "wajada" means knowledge, and the meaning is: Were you not an orphan, and We knew your condition, so We sheltered you? The wisdom behind this is to remind the Prophet of Allah's blessings and to strengthen his heart with His kindness, protection, and support. As Ibn Kathir explained, Allah sheltered him after his orphanhood, took care of him, then supported and protected him.