Give the hanging-band 90/90 split squat a shot. This unique exercise will ramp up stabilizer activity from the core down, so check your ego at the door and don’t go too heavy. Once you return to conventional split squats, you should experience a noticeable improvement.
The key with the 90/90 version is to go straight down with the back knee as opposed to going forward with the front knee. Lower the back knee until it’s just shy of touching the floor, pause, and then return back to the original position under control. The legs should form right angles at the bottom position.
The 90/90 split squat increases activation of the glutes and adductors, and using hanging-band resistance heightens stabilizer activity from the core down. A word of warning, this exercise is more challenging than it looks!