@smart448 Hi! I had the same issue and found a solution for me! Setup a video to show what I did! How to Fix Cutscene Brightness in Assassin's Creed Valhalla!
I was having brightness issues during cutscenes and found that turning off depth of field resolved the issue. See short video for reference: How to Fix Cutscene Brightness in Assassin's Creed Valhalla!