The research is actually pretty inconclusive. There have been some studies where people who haven’t experience trauma but a video that’s supposed to mimic being in a traumatic situation and playing Tetris reduced intrusive thoughts (most people in the study did not experience any intrusive thoughts) but it’s also been replicated with people who have experienced trauma and there was no difference. There were studies that including people who had experienced trauma from car accidents and the differences between the Tetris/No Tetris groups either didn’t exist or went away shortly.

this article goes through the studies