Not sure what you're talking about, but 9950X3D already matches the 9950X in multi-core work in 95% of cases and often beats it. There is no multi-core penalty for v-cache with Zen 5 on any of the X3D models, unlike Zen 4. Other than cost, regular Zen 5 makes little sense now even for productivity.
AMD is reportedly going to release new Zen 5 CPUs in the first half of 2026. Moore's Law Is Dead claims that the Ryzen 7 9850X3D and the Ryzen 9 9950X3D2 both use new CCDs with enhanced boost clock behavior.