Apparently there is a Navi 12 gpu in the works.

Navi 10 – 5700, 5600 series
Navi 14 – 5500 series
Navi 12 – ??

Czech website diit.cz speculates that Navi 12 could be custom gpu for Apple /…

is Navi 12 = Navi 10 + HBM (for apple)

Source: [H]ardOCP – is Navi 12 = Navi 10 + HBM (for apple)