Rather then retcon away tons of continuity, it was instead revealed that when Bruce though Betty had died due to the cancer, instead her father had her frozen until he could find someone else to cure her. Eventually Ross came across The Leader and the Intellegencia, who turned her into Red She Hulk. Cutting lose was definitely her thing, and she was lost in the identity until she almost killed her father, that snapped her back to reality.
Of course, rage still Hulk’s her out, and Red She Hulk hates puny Betty.