“But Yahweh raised up.” Judges 2:16-23 starts a new section of Judges and basically describes the cycle that goes throughout the rest of the book. Israel sins, Israel is defeated and enslaved; Israel cries out to God for help; God raises up a judge to deliver Israel; Israel ignores the judge and gets caught up in sin again; and the cycle repeats.
“judges who saved them.” In this verse, it is the judges who saved Israel, but in other verses, Yahweh is said to save the people. Both statements are true: Yahweh and the judges worked together to save Israel.