Mac timekeeping relies on accurate system clocks. To ensure synchronization, Macs should connect to Apple's Time Server automatically via the Date & Time settings, allowing for auto timezone adjustments through Location Services. Issues can arise if Location Services are not enabled, especially in Virtual Machines. Accurate time is crucial for file timestamps and security; misalignment can cause problems, particularly when using VPNs. Since macOS 10.13, synchronization is managed by a service called timed, and users can also use the sntp command for manual adjustments. It's generally better for clocks to be slightly slow rather than backdating, which can disrupt time order and processing.
https://eclecticlight.co/2025/05/21/system-time-clocks-and-their-syncing-in-macos/