I recently acquired a 50 series NVidia GPU and was unable to get DLSS 4 multi frame gen working in any of the supported titles before realizing that HAGS (Hardware-Accelerated GPU Scheduling) is required to be enabled for it to function. If you are having trouble getting DLSS 4 to work with a supported GPU make sure that you have not accidentally turned HAGS off in the past like me. Hopefully this saves someone a few hours.