How do Biblical Unitarians understand the connection between Mark 1:1-4 and Malachi 3:1-5?

I'm aware someone asked this question already, but they no longer have an account, the post has no answers, and I'm hopefully going to reformulate the question in a way that hopefully explicates the objection more. Mark 1:1-5 states (verse numbers removed): >The beginning of the good news about Jesus the Messiah, the Son of God, as it is written in Isaiah the prophet: “I will send my messenger ahead of you, who will prepare your way” - “a voice of one calling in the wilderness, ‘Prepare the way for the Lord, make straight paths for him.’” And so John the Baptist appeared in the wilderness, preaching a baptism of repentance for the forgiveness of sins. Mark's quotation is seemingly a conglomeration of a few Old Testament passages, but of the passages he does use from Isaiah and Malachi that are relevant, they both say essentially the same thing. Malachi 3:1 (Emphasis added and verse numbers removed): >“Behold, **I** will send **My messenger**, who will prepare the way before **Me**. Then the Lord whom you seek will suddenly **come to His temple**—the Messenger of the covenant, in whom you delight—see, He is coming,” says the LORD of Hosts. So in Mark 1 we are introduced to two figures, Jesus, and John the Baptist. In Malachi, we are introduced to two figures, God, and the messenger, who will prepare the way before God. Notice that immediately after describing a messenger who will come and prepare the way, Mark launches into his description of the ministry of John the Baptist. Since we know that John the Baptist's purpose was to bring in Jesus' ministry, that means that John the Baptist is the messenger making the path straight for the Lord, Jesus. But that means Jesus must be God. To break this down into a syllogism: 1. The Old Testament speaks of a messenger preparing the way for God to meet his people. 2. Mark identifies this messenger as John the Baptist. 3. John the Baptist was preparing the way for Jesus to make his people. 4. Therefore, Jesus is God as described in the Old Testament.