These shots are a bit old, but thy're all we have until Genesis decides to leak a bit more info. The test mule seems to have a lot of rivets in the front so we're most likely going to see a front similar to what you'd find o the current G80. I'm guessing the overall size should be similar to the Hyundai Santa Fe test mule.
https://www.motorauthority.com/news/1115080_2020-genesis-gv80-spy-shots

https://www.motorauthority.com/news/1115080_2020-genesis-gv80-spy-shots