[ckilmer]

I’ve heard guys argue that Melchizedek—the guy Abraham tithed who was the King of Salem—was not an anomaly among caananites in the region. rather his worship of the one true God was the rule. That in the +-700 of years between Abraham’s tithing and Joshua’s return to the area—the Caananites declined into apostacy and awful temple practices—perhaps caused by doubt and drought.

I’d like to hear other narratives of what happened to the caananites during the period between Abraham and Joshua.

[jjotto]

If Melchizedek was Shem, son of Noah, then Canaanite Jebusites must have conquered Salem between Abraham and Joshua.

https://www.aish.com/atr/Where-Was-Salem.html

… In fact the Sages identify Salem (“Shalaim”) as none other than the holiest city in the world, Jerusalem (Targum, Bereishit Rabbah 56:16; see also Psalms 76:3 where Salem is used in reference to Zion). The Sages also identify its king Melchizedek as none other than Shem, the son of Noah (Targum Yonatan, Targum Yerushalmi, Talmud Nedarim 32b).

(Melchizedek was more a royal title than a personal name, similar to the titles Pharaoh and Abimelech. See Joshua 10:1, where the king of Jerusalem is similarly referred to as Adonizedek. The commentators, with some variation, understand Melchizedek to mean “king of the place of righteousness.”)…

[fso301]

I’d like to hear other narratives of what happened to the caananites during the period between Abraham and Joshua.

I can't add much but I have read similar to what I believe you have read.

[Cronos]

There are the Amarna tablets dating to 1500 to 1300 BC