Are you using an Intel Mac or an Apple Silicon Mac? This is very important since the game may not be compatible with an Apple Silicon Mac.
Check the Steam forum for the game to see if anyone has comments regarding issues running on an Apple computer and your version of macOS.
Make sure your Mac meets or exceeds the Recommended System Requirements. You will never have a good gaming experience if you only meet the Minimum System Requirements since you would likely need to lower game settings significantly. I believe this is an older game, so its macOS or hardware models may never have been updated to reflect more recent Apple hardware (especially an Apple Silicon Mac), or more recent versions of macOS.
Make sure you close all other open apps just in case they are using too many resources which the game may need.
If you are running any anti-virus apps, cleaning/optimizer apps, or third party security software, then uninstall them by following the developer's instructions. These types of apps are not needed on a Mac, plus they usually cause more problems than they solve and they can severely impact system performance.
