After migrating from 7.14.5 to 8.7, I could not save passwords in the outbound email accounts. Went to studio and id a reset (did not help) So I removed the password field (saved deployed) I put it back in and now the password just shows in plain text when listing all outbound accounts.
Further more both the mail_smtptype and the mail_sendtype have the same label LBL_MAIL_SENDTYPE
Maybe it is a bug. You can raise it on the GitHub.
Did you try to change the label?
I have not tried that yet because this is secondary. Seeing the password in clear text is really bad for our ISO certification So not too happy about that one 