I'm having the same problem. I launch the game from Steam and get hit with a black screen and spinning beach ball. Have tried several times and have tried verifying the local files through Steam as well. Here are the specs on my machine:
macOS High Sierra (10.13.4)
2017 15-inch MacBook Pro
2.9 GHz i7
16 GB RAM
Radeon Pro 560
Thanks for working on this issue! Can't wait to get into the game.
Radeon Pro 560