I've been able to resolve this issue by enabling Gmail's "Undo Send" feature. `CMD` + `Enter` still triggers sending, but I now have a 10-second window to catch it before it is actually sent.


[Send or unsend Gmail messages][2]

1. On your computer, open Gmail.
2. In the top right, click Settings .
3. Click Settings.
4. In the "Undo Send" section, check the box next to "Enable Undo Send."
[![enter image description here][1]][1]
5. In the "Send cancellation period" section, set the amount of time you want to decide if you want to unsend an email.
6. At the bottom of the page, click Save Changes.

**After you turn on Undo Send, you can cancel sending an email.**

1. After you send a message, you'll see the message "Your message has been sent" and the option to Undo or View message.
2. Click Undo.


  [1]: https://i.sstatic.net/1sGeA.png
  [2]: https://support.google.com/mail/answer/2819488