Well, the hide calendar events doesn’t work because it affects all calendar apps, but I’ll test disabling notifications. Although I don’t understand why the normal way to disable notifications doesn’t work for this app.
My “notification” screen looks differently than yours. I don’t have the “Behavior” entry where you change to “Show silently and minimize”. I went through all available settings with a fine comb, and can’t find one to really get rid of the notifications
EDIT: What Android version of /e/ are you using? Mine is Android 10
I am also wrestling with this problem, on Android 10. The fact that we cannot disable them, and can ALSO not silence their notifications is incomprehensible.
Anyway, for Calendar I found a solution: disable all it’s permissions: Settings >> Apps and notifications >> Permissions. Specifically, it is possible to deny “Calendar”.
But for Tasks, this is not effective: although it has NO permissions, it still keeps giving notifications.
I have asked for help about this: How to disable Tasks-app notifications?.
— now I found a workaround. See there.
By the way, in Nougat, it is possible to silence Tasks.