OneCal is a productivity tool that aims to make calendar synchronization as easy as possible. It has a very intuitive UI, supports multi-way syncs, and is fully configurable (you can choose to sync event titles, descriptions, and participants, assign colors to clone events, exclude events from syncing by assigning them colors, and much more). You only have to connect your calendars and create a sync with the desired configuration, and you won’t have to worry about the rest as the calendars are kept in sync automatically.