https://royals.ms/forum/threads/how-to-fullscreen-on-osx.10014/ I saw this guide here by @amadeuszxd and this method works just fine but will by default be 800x600 resolution and will probably have black borders, you can totally change all of this by editing the info.plist If you haven't done anything for fullscreen, the first box will look like this: <key>Fullscreen</key> <false/> Just go ahead and change it to <true/> and the game will forever load in full screen, and you can just cmd+enter/alt+enter to window mode it. And for the second box, you can then change the resolution to whatever you want. Enjoy!
