If main focus is deliverability and encryption plus privacy

You can try with mailbox or posteo with email, and self host etesync for calendar

data-wise, OsmAnd and Organic both use OpenStreetMap so there’s no difference. I am not sure the second error in your post is a osm problem or it’s just osmand

I would say Fedora workstation if you hate the idea of getting arch-like distros but Manjaro if you just dislike the daunting procedures to get your arch work