Yeah, the new raptors and engine bay redesign for version 3 of ship seem a lot more robust than version 2, very impressed that the ship finished its mission so well.
Scott Manley goes into quite a bit of detail on analyzing superheavy’s failed boostback, it’s a good watch:
TL;DR - seems like the hot staging kicked the booster out in the wrong direction, and the ship’s plume impacted one of the grid fins, which would’ve given it quite a big kick. The sloshing just from that could easily have caused the observed issues.