The interesting thing about this is that the Bible tells of God's relationship with mankind, detailing his relationship with certain people after Adam -- particularly Abraham, Isaac and Jacob. God knew there were other gods people worshipped or gave reverence to. It is outlined in the scriptures for us.
Yes --- nail on head - If one read the OT book - Abe and Melchi
Zedek are offering Sacrifices to the "Most High" -- and the God the are worshiping is not named YHWH .. as told to us by YHWH some 500 years later when he talks to Moses.
Melchi
Zedek is the "Priest-King" of Jerusalem at the time .. a Canaanite walled city -- City Patron god is Zedek. The God they are worshiping is not Zedek however but "The Most High" God of the Canaanite Pantheon EL. Mentioned as such in other places in the Bible .. Psalm 82 -- "Council of EL - Assembly of EL" named as such because EL is the Head of the Divine Assembly . Chief God .. the Most High.
So no YHWH worship going on until Moses .. and even those such as ABe only worshiped on God .. they still believed in the Pantheon .. just chose to worship only on.
After Moses .. YHWH is revealed .. The People might have worshiped YHWH only for a short time - but after 2 years - Moses leaves for a few weeks up to the mountain .. People start worshiping EL -- "golden calf" -- and could have been concurrent with Asherah .. sometimes accompanied by the son = which was "The Baals" to other nations .. but was YHWH to the Israelites. EL has 70 Sons who end up fighting for El's position on Earth .. In Deut 32:8 (need to get a proper reading) EL "The Most HIgh" El Elyon -- alots the nations of the earth to his Sons .. YHWH's portion ends up Israel. .. these sons then end up fighting for El's position .. as detail every time they attack some city.
After this time .. the Israelits are raging Pagans for their entire history.. basically until Josiah's reforms -- which are only a few years prior to the End .. when Marduk defeats YHWH and destroys the Place where his Name Resides. aka -- Blots out his Name.
When YHWH Was worshiped .. it was along side many other Gods .. there were various Places of Worship for YHWH .. the typical Temple you would find at least 2 Standing Stones .. one for YHWH the other for Asherah .. his consort. -- the sons always take on the consort of the father in this motif. El is still around though .. relegated to "Most High' in the heavens .. YHWH now Chief God on Eearth - or rather .. one of those vying for that position.
At YHWH's temple you would find both male and female prostitutes .. what ever your preference .. and a "High - Place" out back -- in case you were needing a big favor -- requiring a hefty sacrifice .. of the first fruits as was required of Jephthah