Well Assassin’s Creed Valhallah just got updated today and it apparently fixed most of the performance issues on Xbox while now performance on the PS5 isn’t so good:
I think folks need to remember that we’re in a pandemic and studios with thousands of people are trying to craft and then fix incredibly complicated pieces of software to run across 7 different platforms, including three of them which are brand new with relatively immature development tools.
Things are going to be inconsistent and rough for at least the next 3-6 months.