I'd like to to start a second instance of Mail.app in macOS 10.14 for another email account.
I found this post about opening a new instance of Chrome: How to open new windows as separate application instances for Chrome, Terminal?
and tried the Terminal commands but the catch is that they do open a second instance of Mail.app but also with the same account credentials that are already there. I want to start "from scratch" with the second instance and input whole different credentials.
There used to be a program "SwitchUp" a couple of years ago but it's not being developed anymore.
Anybody an idea if this is possible (without switching to another user account)?