I wonder if I could be any good at Android development, because I'll be damned if there isn't still a need for a Google Calendar reminders workalike in Y2K19. (A mission-critical need for me, at any rate, and I suspect others who have a complex relationship with linear time.)
But like. It'd be so much more a thing I might actually do if I could get even $50/mo out of it. And I would open source it and I just don't know how well beg-ware gets compensated, even for cool fedi devs.
Dont know what you looking for, if this may be any use or if you may already know about these-
I use Etar as my calendar with Calendar Notifications
Etar - OpenSource Calendar https://f-droid.org/app/ws.xsoh.etar
Calendar Notifications (Advanced calendar notifications) - https://f-droid.org/app/com.github.quarck.calnotif
Also offline calendar for on device calendar & DAVx⁵ to sync Nextcloud calendars
Offline Calendar - https://f-droid.org/app/org.sufficientlysecure.localcalendar
DAVx⁵ (CalDAV/CardDAV Synchronization) - https://f-droid.org/app/at.bitfire.davdroid
@dazinism Currently I'm using aCalendar+ (paid, even) with DAVx5 syncing it to a back end on my little home server, btw.
None of the apps I've found, to-do apps, notification apps, etc, offer the same UX of Reminders in gcal which really works well for my brain and integrates well with the phone OS.
So that's why I'm thinking about writing it. Of course given life factors that's a LOT harder than it sounds.