In the canonical gospel accounts, God's spirit enters Jesus when John baptizes him. Then he starts his ministry which includes miracle working. The disciples did the same thing in Acts after receiving the spirit. There is an even a false prophet (from the Christian POV), Simon Magus, who could perform some miracles.

There was widespread belief in miracle working in the ancient world. It meant the miracle worker had been empowered by the gods, or was a son of a god (or Yahweh in the case of Jesus).

So we lack sources to say if he was considered a magician or not to be honest.

How do you know? What other historical documents did he write that we can compare to what we now understand of the historical record, in order to judge his quality as a historian?

When Luke wants to locate the start of John the Baptist's ministry in time, he says, "In the fifteenth year of the reign of Tiberius Caesar, Pontius Pilate being governor of Judea, and Herod being tetrarch of Galilee, and his brother Philip tetrarch of the region of Ituraea and Trachonitis, and Lysanias tetrarch of Abilene, during the high priesthood of Annas and Caiaphas, the word of God came to John the son of Zechariah in the wilderness." We can check that all those people were in those positions at the time Luke said they were. He's tying the events he's narrating to a specific, concrete historical setting.

One little thing that I notice: When he's writing Acts, Luke is at times part of the events. He's describing Paul's travels, but sometimes it's "he", and sometimes it's "we" - that is, Luke is traveling with Paul. And whenever it's "we", the level of detail goes up. The ship had this figurehead. Here's where we sailed, day by day. But when Luke's not part of the party, he doesn't know at that level of detail, and he doesn't say what he doesn't know. That's a careful writer.