VideoCardz reports AMD CEO Lisa Su basically confirmed at CES 2020 that there will be a high-end variant of the Navi architecture:
Gordon Ung, PC World: Do you think that AMD has to have a high-end competitor in the discrete graphics market?
LS: [laughs] I know those on Reddit want a high end Navi! You should expect that we will have a high-end Navi, and that it is important to have it. The discrete graphics market, especially at the high end, is very important to us. So you should expect that we will have a high-end Navi, although I don’t usually comment on unannounced products.
The website heard from sources at board partners that "Big Navi" is looking pretty good. The card is reportedly based on next-gen RDNA, which has higher energy-efficiency than the current generation. However, AMD's board partners are worried about NVIDIA's 7nm RTX 30 series, as they have no idea what to expect. If recent rumors are accurate, the upcoming Ampere generation from NVIDIA could be a significant upgrade.
AMD's Big Navi may hit the market in June (at Computex) or July (one year after the RX 5700).