"...the one in the middle [at Mamre, Genesis 18] is Father of the Universe, who in Holy Scripture is called by His Proper Name, 'I am that I am'; and the beings on each side are those most ancient Powers which are always close to the Living God, one of which is called His Creative Power, and the other His Royal Power. And the Creative Power is Theos, for it is by this that He made and arranged the Universe; and the Royal Power is the Kyrios, for it is fitting the Creator should lord over and govern the creature. Therefore, the middle Person of the three, being attended by each of his Powers as by body-guards, presents to the mind which is endowed with the faculty of sight, a vision at one moment of One Being, and at another moment of three..."
Canaanite references to 'Melchizedek' appear in communiques to the Egyptian Pharoah c.1400 BC. Melchizedek as the Royal Personage in Ezekiel's Exagoge (c.150 BC?) is another topic covered previously. Melchizedek was Kyrios-God long before Yahu, apparently.
That the Royal Power should be divine will surprise no one. But this tradition did not begin with Alexander, nor with the Jews themselves. In Egypt from at least 2575 BC and thereafter, the Pharaoh was -- as "the Good God", i.e. Horus, Re, Osiris, etc. -- typically the object of direct worship in the national cult. And Canaanites picked this up from their Egyptian overlords; see for example Sigmund Mowinckel, The Psalms in Israel's Worship [1962/2004], p.187:
From the number of set hymnic phrases which occur in the letters of homage from Canaanite princelings to the Pharaoh of the Amarna age – 15th and 14th C. BC -- scholars have concluded that the writers were using well-known expressions and quotations from the religious hymn literature in order to express their devout submission to their divine overlord, the 'Good God' of Egypt.75 Both expressions and metaphors in many ways agree with the divine hymns from Mesopotamia and Egypt. This proves that the international psalm style was well known in Canaan, so that terms and ideas from the latter would flow easily from the pen of the Canaanite scribes. No doubt they were familiar with them from their own temples and the cult there, which at that very time was strongly influenced by Egyptian religion and style.
75. See Franz Böhl, “Hymnisches und Rhythmisches in den Amarnabriefen aus Kanaan” in Theologisches Literaturblatt, Vol.35 [17 July 1914], p.337ff; De Psalmen 1 [1946], pp.25ff.; Anton Jirku, "Kanaanäische Psalmenfragmente in der vorisraelitischen Zeit Palästinas und Syriens," The Journal of Biblical Literature, Vol. 52 (1933), pp.108ff.; Geo Widengren, The Accadian and Hebrew Psalms of Lamentation as Religious Documents: A Comparative Study [1936], pp.5ff.
75. See Franz Böhl, “Hymnisches und Rhythmisches in den Amarnabriefen aus Kanaan” in Theologisches Literaturblatt, Vol.35 [17 July 1914], p.337ff; De Psalmen 1 [1946], pp.25ff.; Anton Jirku, "Kanaanäische Psalmenfragmente in der vorisraelitischen Zeit Palästinas und Syriens," The Journal of Biblical Literature, Vol. 52 (1933), pp.108ff.; Geo Widengren, The Accadian and Hebrew Psalms of Lamentation as Religious Documents: A Comparative Study [1936], pp.5ff.
Late-comer Jesus as 'the Good God', a messianic "Good Shepherd" (Ruler), and "King of the Jews" all make perfect sense from a (Judeo-) Egyptian perspective. That sort of rhetoric/characterization was ancient, familiar, expected in (Alexandria) Egypt.