If the Lord Jesus Christ is the true God in this verse, it wouldn’t refer to Him as “the image of the invisible God". Indeed, man is made according to His image (Genesis 1:27). Additionally, if your interpretation is accurate, does it mean that the true God was created, since the verse states that He is “the firstborn over all creation”? There is only one true God, the Father (as stated in John 17:1-3; Malachi 2:10).Colossians 1:15-16
15 The Son is the image of the invisible God, the firstborn over all creation. 16 For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him.
Jesus is more than a messenger. He is God made flesh.