Did you read the screenshots? Abraham recognizes Melchizedek’s God as an older tradition in line with his. Not tribal, hence the “all peoples” promises.
However, he does not accept anything from Bera, king of Sodom, even though he helped him defeat the other kings. He had discernment.
There is no syncretism there. That’s part of why Israel clashes with folks throughout history—they try to impose their religion or messed up culture on Israel. It’s also why Israel clashes with God—syncretism does creep in, along with its practices, and he has to deal with it.
Some of what you said I’m not addressing, because it would take time to … do it justice. It is done elsewhere.