The story of Philip and the Ethiopian eunuch says “an angel of the Lord,” not the “Angel of the Lord.” My understanding is that The Angel of the Lord is Jesus himself.
Nevertheless direction, a command, was given to Philip on behalf of the man searching the scripture.
Later, the Holy Spirit moved Philip to a different location after helping the Ethiopian man.
The debate is whether this miraculous activity of the Spirit still occurs now. Some say that it was manifested particularly at that time to establish the church.
I do not want to be guilty of “quenching the Spirit.” I do not want to place anything out of the possibility of God.
The beauty of the story is that the man’s studious and zealous personality was recognized by God and the man was immediately rewarded with teaching and understanding. Additionally, it is evident that a person of different nationality was welcomed into the Kingdom and rewarded for his effort to understand the Scripture.