The rumor mill said AMD hedged its bets because of TSMC N3 uncertainty. Remember these decisions are made years in advance. I think they will end up with the Zen 5 chiplets on N4 and Zen 5c chiplets on N3. And there's talk of other chiplet variants like a subtly different one for Strix Halo.
The node really doesn't matter. It's a decent enough increase, but it's the same basic design carried over from Zen 2. Zen 6 is set to be a lot more interesting if AMD switches to something like a die-to-die interface (Infinity Links) like
High Yield predicts. That's also when we can expect core count increases, and maybe different ways of using L3 cache.
Zen 5 can be cheaper on N4 than N3, so that's a potential point in its favor. We've also heard that
AMD might try something different with 3D V-Cache this generation, but no word on what that actually means.