Hello i am also curious on the way people send a "new ticket" mail to support mail box when an issue is created on IT next gen process.
From what i see a mail is sent to the contact that create issue but as all others fields are empty like assignee / watcher no one will get a mail.
I see in settings the "new request" mais but as stated before all values are empty and more i dont see any "mailbox group"
One way we will test but have drawback is to add a "fake user" with email = support mailbox and choose it as "Project Lead" + "Default assignee" in the "project" settings main page, so we hope a mail will be sent to default assignee then to support box.
One of the issue is that it will "cost" 1 agent just for a missing feature.
Other way would be "automation" needing time to create a valid mail template...