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Are you seeing any improvements when smashing with the lacrosse ball?
This is a place to start, but sounds like you need something else to resolve it.
Have you used a barbell or plate as is done here?
Episode 208: Wide Stance Prep or Fixing Sumo+Decompression
A couple other ways to hit it here
Episode 173: Improve Your Medial Chain Dominance
Episode 36: Spinal Mobility; Box Squat Groin Torture; Spine Rot/Adductor Stretch
Have someone smash it for you like here
Episode 14: Celebrity Goat Death Match: Chris Spealer
Keep working at it and identifying things upstream and down stream of where you are seeing it.