The whole N5P rumor was about AMD jumping in to fill N5 capacity at TSMC freed by Huawei/HiSilicon no longer being allowed to order more there. Nobody denied that AMD is working with 5nm. Much of the discussion was about the timing and how realistic was AMD doing what the rumor claims this autumn already, with some even suggesting Zen 3 would be duplicated on that node.
And unlike mere refreshes works with new nodes are a huge financial undertaking so it does matter very much whether investors are being informed about it happening.
If the next generation is going to be at 5 nm, then they would almost certainly already be working on it, which could have lead to the rumors. I think several past rumors have actually been confusion between different generations that were being worked on at the same time, at different stages of development.
It is unclear what the next generation will actually be called. I am expecting Zen 3 as Ryzen 4000 desktop parts to use roughly the same IO die as current Ryzen 3000 parts. For Ryzen 5000 ( Zen 3+ or Zen 4?), I expect almost the same cpu chips or possibly a die shrink combined with completely new IO. Zen 3 is a new architecture, they may tweak it, but I wouldn’t expect much changes right away.
With the release of the XT Zen 2 base parts, I am wondering if the initial Zen 3 parts will actually be large cache (>32 MB) HPC parts on 7 nm (server first). The desktop parts may come later and I would expect that they will still be 7 nm also.
AMD has been making the APU based on the previous generation; Ryzen 4000 APUs are Zen 2 based. I could see them wanting to change that, so perhaps they are working on getting a Zen 3 / RDNA2 APU out on 5 nm as early as possible. They would want both for better power efficiency.