[Question] Pascal’s Mugging and abandoning credences

What are the theoretical obstacles to abandoning expected utility calculations regarding extremities like x-risk from a rogue AI system in order to avoid biting the bullet on Pascal’s Mugging? Does Bayesian epistemology really require that we assign a credence to any proposition at all and if so—shouldn’t we reject this framework in order to avoid fanaticism? It does not seem rational to me that we should assign credences to e.g. the success of specific x-risk mitigation interventions when there are so many unknown unknowns governing the eventual outcome.

I hope you can help me sort out this confusion.