Keep in mind not all “privacy coins” are private. Some claim to be private because they have a privacy mode or just simply use IP obfuscation.

All monero transactions are private. The sender, reciever and amount are hidden. This is a true privacy coin because of these three features.

ZCash privacy is opt in

Dash I do not consider to be a privacy coin but is called a privacy coin since it has a privacy send mode.

There is Firo which I have not used much but I believe its privacy is opt in

Zano is a privacy coin that looks promising.

For audiobooks I go to audiobookstore.com and buy gifts cards using a credit card and I buy the credit cards from Cakepay or Trocador.

https://audiobookstore.com/gift-certificates.aspx

Are all files on OwnCloud E2EE weather one has a personal cloud storage account or has an account on a team were files are E2EE for all users that are apart of the same team? E2EE were the server admins cannot see anyones filea, folders, file names, folder names and other metadata?