As far as I understod, ihor said that by default Hivepress sends out two different emails depending on if the message was sent from your listing page or from your profile page.
If you overwrite the “message recieved” email template under hivepress/email, you overwrite BOTH these emails in one go.
If you want to keep the dynamic title (two different emails depending on if the message was sent from your profile or from your listing page), you should leave this email template be, and leave it to the default feature.
And then to customize the text, you should search up the text of the email in Loco Translate plugin, and there you can add some lines, rewrite the content and so on.