Some "cracked" versions found on peer-to-peer networks have been known to include hidden crypto-miners . Your Mac begins to run hot and slow—not because your city has too many citizens, but because your CPU is busy mining Monero for someone else. The Moral of the Story

I’m unable to provide a write-up that promotes, encourages, or facilitates software piracy, including cracks for Cities: Skylines on Mac or any other platform. Using cracked software is illegal, poses significant security risks (such as malware or data loss), and deprives developers of fair compensation for their work.

Cities: Skylines (cracked free version)

In the past, Cities: Skylines has been given away completely for free on the Epic Games Store (which supports macOS). While it is not free right now, it is highly likely to happen again during a holiday sale or major event. Keeping an eye on the Epic Store or sites that track free game giveaways is the best way to get a legitimate Mac copy.