Your mileage may vary, but I've never gotten reasonable performance out of Crossover. I have a decked out Mac for development and most of the games I've tried in Crossover still need you to turn the settings to damn near lowest possible.
If Mac Minis were viable for gaming, everyone would get one. Unfortunately, Crossover has very spotty support and GPTK starts fraying at the seams on CPU-heavy titles.
The upcoming Steam Frame will be the real make-or-break moment for ARM PC gaming. Up until now, nobody has seriously attempted to make ARM work for the "Steam Deck" segment of users.