Are you working on mobility up/down stream of the knee?
Tightness or mobility limitations can cause you to make compensations during the movement that may or may not be aware are happening.
What are sliding surfaces around your knee?
Sometimes pain can come from adhesions pulling in opposite directions or tacked down skin.
Restoring the sliding surfaces allows your skin and muscles& tissues to move independently of each other.
Is there a coach that can look at your technique when squatting?
Video taping can help too so you can see exactly what is happening.
As you noted a 30 degree turnout is too much. You want your feet straightish 8-11 degrees.