The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
Chances are your inability to sit cross-legged IS indeed having a poor effect on your squat, and it’s probably going to take a look around the whole hip to clear it all up.The super frog is definitely a good option. It will help you improve
your ability to drive the knees out in the squat, and also get them
closer to the floor for that cross-legged position.
You’ll also probably want to take a lacrosse ball to those glutes and hamstrings too. Any mwods for improving the squat that are hip-centric (hip flexion, external rotation, and abduction) will probably improve the cross-legged position too. Leaf through the squat mobs, and look for some hip action.