Pretty much the most reliable news outlet in Japan says March 2022 release date for the Z (which aligns with the job 1 production start in January 2022 Carmaker1 and NissanFreak81 have reported):
https://bestcarweb.jp/news/scoop/246804
Also, a refresh with a mild-hybrid for the GTR by the end of next year.
Disclaimer: while this is what is PLANNED, still not holding my breath as Nissan executives could pull the plug on those plans at any time with the red ink and pandemic.