It sounds like EteSync is exactly what you're looking for. A hosted NextCloud instance + DAVx5 is admittedly a bit lacking in the "full privacy" department, and Proton or Tutanota doesn't integate with the standard calendars, but both would also be valid options IMHO.
It sounds like EteSync is exactly what you're looking for. A hosted NextCloud instance + DAVx5 is admittedly a bit lacking in the "full privacy" department, and Proton or Tutanota doesn't integate with the standard calendars, but both would also be valid options IMHO.