for 1080p gaming? a long long long time. the 2080 is overpowered for 1080p. that is a 4k class card. no reason to wait.
My 955 black and Hd 7950 are fine for 1080P gaming (medium), and they are old AF.
you could be fine with a ryzen 1200 and a 1060 for 1080 gaming for a while.
Pull the trigger!