I have 2 issues I just found it’s that the game shows a black screen when not in borderless windowed mode and the game crashes when loading any map it happens when I try out an skin and it also happens when loading a map in any other mode.
We are aware of some of the black screen issues in full screen mode.
For the crashes, it appears that the Mac is currently on Mojave
10.14.1, could you try updating to 10.14.6? This is the latest version for Mojave. If the crashes persist, could you include the crash report ID or more details on what happens after it crashes?