I loved Chaotic-AUR when I was using Arch. No waiting to build AUR packages, you know if it works right away.
You have to decide if you trust the source. Personally I’m not worried.
Also if you know how to fix an AUR package you can open a ticket on their github and they will update it immediately most of the time.
what about Posteo? when I compaired many providers a few years ago they seemed like one of the the most ethical
one caveat: you can’t use your own domain name, for privacy reasons. I wish they gave the option though. maybe it has changed since
no idea about calendar invites