Ugh, no app for iOS. They do have a beta for Android.
https://proton.me/blog/calendar-free-web-android
Looks like they support shared calendars:
https://proton.me/blog/calendar-free-web-android
Looks like they support shared calendars:
Ah well, maybe I just need to give a few of them a try and see what they're like. I'm increasingly uncomfortable with having Google be such critical part of my life.