For now some of them are using crypto coins, mostly Bitcoin, but if they will agree on a common coin shared between them, it will be a serious blow to the US Dollar supremacy even not from the start but on the long term. Also, other coins used in international transaction will be affected like Euro, UK pound, Swiss franc, e.t.c.

This will lead to a seriously US Dollar inflation but also some of the other mention coins.

Hello

We are using for years home and business gnupg (for public/private keys) + pass + QtPass + git (for remote central storage). We are using it even as a team with shared keys.

Hello.

Have you tried an FOSS XMPP server solution ?

Just replace your entire Microsoft email server with a self-hosted FOSS Linux email solution, where you can have unlimited email accounts.