Roughly, GeForce next will be SEC 4LPP (custom 5nm EUV for NVDA). Hopper will be TSMC 5nm MCM for heavy compute workloads. Both are under nearly parallel development for a close release date. The interesting part is that Nvidia can easily change the target segment of each design to counter RDNA3 (for example if monolithic AD102 is not enough to keep the gaming crown, they can do a crazy 4090 MCM for gamers). Nvidia bought lot of 5nm capacity from TSMC for 2022. They can do it.
One thing is sure, if people think that Nvidia will let RDNA3 shine, they don't understand Jensen and his ego. "Whatever the price" my friend told me...