"One by one the cities were taken, and Hazor, the stronghold of the confederacy, was burned. The war was continued for several years, but its close found Joshua master of Canaan. “And the land had rest from war.” PP 510.4 But though the power of the Canaanites had been broken, they had not been fully dispossessed. On the west the Philistines still held a fertile plain along the seacoast, while north of them was the territory of the Sidonians. Lebanon also was in the possession of the latter people; and to the south, toward Egypt, the land was still occupied by the enemies of Israel. PP 511.1"
"So Joshua took the whole land, according to all that the Lord said unto Moses; and Joshua gave it for an inheritance unto Israel according to their divisions by their tribes. And the land rested from war."
EGW directly quotes Joshua 11:23, "And the land had rest from war," and uses it to mark the end of a phase of the conquest, while also acknowledging that the conquest was not fully complete.