Does Magento 2 log mails to the database?
i.e. where did Magento 1's core_email_queue go?
Does it make a difference if Sales Emails -> Asynchronous sending is enabled?
Magento 2 doens't have this feature by default but you can use this free plugin, which catches the emails in the database table experius_emailcatcher
:
Magento 2 Module Experius Email Catcher
Email Catcher / Logger Module for Magento 2.
System > Tools > Email Catcher
Disables all email communications when system/smpt/disable is Yes.
https://github.com/experius/Magento-2-Module-Experius-Email-Catcher