I was able to get fullscreen mode by editing the "SkyrimPrefs.ini" file under "/Users/YourUsername/Documents/My Games/Skyrim Special Edition". Here are the lines I edited on my Macbook Pro 14" to enable fullscreen support:
Please Note: This Forum is for non-application specific questions relating to installation/configuration of CrossOver. All application-specific posts to this Forum will be moved to their appropriate Compatibility Center Forum.
CrossOver Forums: the place to discuss running Windows applications on Mac and Linux
We're rebels. We're misfits. But mostly, we're software liberators. And we're very, very good at what we do. We have to be. Lots of developers work with open source, but only a tiny fraction of those are good enough to get software that was designed for one platform to work on another one. We invented CrossOver software - a unique approach to cross-platform compatibility that does not require dual-boot or another OS license. We launched PortJump to help app and game developers broaden their market beyond Windows® users. And we launched ExecMode to help organizations solve really ugly technical challenges.