I have the exact opposite where squats hurt a damaged area of my back. Can’t really do them with any real weight. So I load up on dumbbell lunges and other leg work. The best I’ve gotten is 5 reps (each side) with 65lb dumbbells (I’m 175lbs)
When I do dumbbell lunges I concentrate on keeping my chest, back and core engaged and when I step forward I also step toward the outside of the leg going forward by about a foot. Helps with stability.