I installed etar, but I fail to see how this is a replacement for Google calendar. It is a nice app with seemingly identical functionality that still reads and

I installed etar, but I fail to see how this is a replacement for Google calendar. It is a nice app with seemingly identical functionality that still reads and works with my Google calendar feed and seemingly nothing else. If Google still hosts my calendar, then this app isn't providing anything of value privacy wise. Am I missing something here? I've been looking for a Google calendar replacement that respects privacy for years. I hear rumors proton mail might get one at some point... but I'm not holding my breath.