Harden system and user services by restricting systemd units to access clock information with the ProtectClock unit setting.
Ntp
Articles about Ntp
Time synchronization is an important system administration task for Linux systems. This guide explains how to configure, and also troubleshoot time issues.
Normal NTP can be difficult to set-up, especially for desktop systems which don't need a very accurate time. The tool tlsdate might be a great alternative.