I think these apps have been neglected for a long time. There are many integration issues with synchronization, caldav, and more...
And I wanted to create a common calendar so one can set reminders for her (and all of us) about medical appointments, medicines and stuff that we all could manage from our phones, wheter Apple or Android, or my computer, via a web browser, caldav or whatever. I imagined that would be second nature, after all it's just a calendar, right?
Well, it's 2023 and you can't do that because reasons.