I have an old @live.com address that I use for everything
You can keep your @live.com email address which i presume is normal IMAP account where the mail is stored on the Microsoft mail server and you can then access it from any device.
When you add the account in eM Client either when you first open the program or in Accounts later, choose the “Automatic Setup” as in example below. Near the end of the email wizard, your browser will open and ask you to “Allow” your @live.com account in eM Client. That’s it.
You can install eM Client v8.2 (1478) for Mac from the version history page for Mac which works reliably according to a couple of users on this forum with OS El Capitan.
Past that version of eM Client you will need to upgrade your Mac OS from other user reports.