Chapter 13

Starts this way:

1 Now Joshua was old and advanced in years, and the LORD said to him, "You are old and advanced in years, and there remains yet very much land to possess. [Jos 13:1 ESV]

So Israel had not yet conquered all the land that God intended for them to have.  That earlier verse, then, was about a "waypoint" or "milestone", not about a completion of the campaign.

Next, God gives Joshua a list of what still needs to be taken. Of note are all the regions of the Philistines, which includes Gaza - still a pain today, Lebanon, also still a problem today.

God tells them to go ahead and divide the land, including these unconquered territories.  Least I think that's what it says.  Then there is a detailed description of the land Moses gave the tribes that stayed on the East side of Jordan.