There is no problem using the default reminders app as it is caldav compatible. So as long as you do not use iCloud I do not see a problem there.
foreverwhatever
joined 1 week ago
I am also using the default apple reminders app but with my selfhosted Nextcloud account, which makes it independent of the apple ecosystem.
As I currently have no android device I can not recommend any apps, but I'm sure there are some caldav (it's a standard) compatible apps which allow consuming the caldav todo list.