Was the Philip spoken of in
Acts 8:6 an apostle ? Yes or No .
No, as the context shows. And doing miracles was something Christ authorized the Seventy to do, and no doubt they with Philip were among the 120 in the upper room. But even so, it required Apostles for those Philip preached to, to receive the Holy Spirit:
5
Then Philip went down to the city of Samaria and preached Christ to them.
6 And the multitudes with one accord heeded the things spoken by Philip, hearing and seeing the miracles which he did.
7 For unclean spirits, crying with a loud voice, came out of many who were possessed; and many who were paralyzed and lame were healed.
8 And there was great joy in that city.
9 But there was a certain man called Simon, who previously practiced sorcery in the city and astonished the people of Samaria, claiming that he was someone great,
10 to whom they all gave heed, from the least to the greatest, saying, "This man is the great power of God."
11 And they heeded him because he had astonished them with his sorceries for a long time.
12 But
when they believed Philip as he preached the things concerning the kingdom of God and the name of Jesus Christ, both men and women were baptized.
13 Then Simon himself also believed; and when he was baptized he continued with Philip, and was amazed, seeing the miracles and signs which were done.
14
Now when the apostles who were at Jerusalem heard that Samaria had received the word of God, they sent Peter and John to them,
15 who, when they had come down, prayed for them that they might receive the Holy Spirit.
16 For as yet He had fallen upon none of them. They had only been baptized in the name of the Lord Jesus.
(Acts 8:5-16 NKJ)
So what is your big point? Context proves the Apostles had unique authority, as God documented in Samaria.
Why Philip baptized them only in the name of Jesus is not explained.
But it is clear, when the Apostles went to be with the LORD, the things only they could do---- would cease.