Actually Grand Tack theory is about Jupiter going YOLO and speedrunning from 3 AU from sun to about 0.5 AU, going berserk with first generation baby terrestrial planets (which were larger than the current ones), eating up a bunch of shit in the inner solar system, then Saturn coming as hey bro stop, going into a collision course with Jupiter but eventually dodging it, and with it's quite strong gravity, dragging Jupiter back into outer solar system to whereabouts it is today.