installed World of Warships Ultra from the official website on a MacBook Pro 2017 with a 15.4-inch display, 2.8GHz Intel i7 7700HQ processor, 16 GB RAM, and Radeon Pro 555 2 GB.
The game client is very likely to freeze when entering battle in "Fullscreen" mode with a suitable resolution (2880 x 1800) even though the general graphics quality is set to "Medium" (about 30fps in the port). Sometimes, no matter which graphics options were selected, the client freeze during the countdown so I had to force quit the app from the desktop or restart the computer by holding the power button. Tonight, I changed the DirectX 9 to DirectX 11 and found there is no more freezing when entering battle in "Fullscreen - Windowed" mode (with a fixed resolution of 1680 x 1050, but I also had encountered freezes at the very end of a co-op battle in "High" general graphics setting.
Thank you very much for spending time reading this, I wish we can eventually figure out the optimum setting of graphics in WOWS.