How to handle customer replies to transactional emails in MemberStack?

Am I missing something or loosing the plot.

So I have set up custom transactional email sender and a custom marketing email sender.

All good. But.

Memberstack make a big deal about these NOT being no-reply etc. 
However if someone replies where so I see those emails.

I know I can set a reply to on a campaign email but that is not my concern.

My concern is people replying to the transactional email. The recommendation is to use support@ for this email. But if someone emails back wanting support were does this go? - there seems to be no reply to option for these transactional emails.

As ms are using resend I tried setting up a reply only email in there but that was a non starter.

Any tips?