Regarding Navi and AMD's Next Gen GPU architecture, from April 2018.
AMD Navi Mainstream GPU to Have GTX 1080 Class Performance, Succeed RX 580
Behind The Scenes at AMD's Radeon GPU Labs
(note: that was before nvidia named their cards RTX 2080/Ti)
Now, if the correct thinking is that Arcturus is not the namee of next gen GPU micro-architecture, but a specific GPU or configuration of Navi, I am wondering if Arcturus is the big chip Navi 20, revised version of Navi or dual-Navi 10 card. or something along those lines. Or even a specific GPU in the Next Gen GPU family, but not the name of the new architecture itself. We've been through this before. Vega was originally known as Greenland as far back as early 2015, and was meant to be the flagship of AMD's Arctic Islands family. It turned out AMD had two new GPU families on the horizon back then, Polaris and Vega.
The Arctic Islands name never became official.
Anyway, here's a follow-up article, also from April 2018.
AMD RX 600 Series GPU Project "Zen" Detailed – Radeon on Steroids to Amp Clock Speeds & Efficiency
How all of this impact next gen consoles, we'll have to wait and see. But I wouldn't put it past Microsoft to get AMD to engineer a GPU that uses most of the next gen feature set, like they did with Xbox 360's Xenos GPU for 2005. The unified shader architecture that ATI made for Xbox 360 did not show up in Radeon cards until Spring 2007.