Setting mailcow as a local cache/relay

Lockszmith

Hello, I’m intrigued by mailcow, but terrified from managing a mail domain for personal use.

My domain’s email is currently on a free Google Workplaces tier (grandfathered from the days of Google for Application was freemium).

My question:
Could mailcow be used as a forward/cache/relay that uses an already established SMTP/POP3/IMAP public server as it’s backend?

In my internet searches in the past year, I could not find anyone trying that approach.
Has anyone here done it?
If not, does anyone have any ideas about the general architecture of this?
Which component will I point at the SMTP server?
Which component will I point at a POP3 endpoint?

Lockszmith

I’m probably asking the wrong question.

If I understand correctly,
[A] Postfix is used for sending out the emails. While access to the email is done via SOGo or Dovecot.
SOGo will also supply the ActiveSync interface for Outlook (desktop and or client) + Web GUI.

[C] If I understood [A] and correctly, what I’m asking is whether SOGo can allow me to retrieve email from POP3 and send via a remote SMTP server (not Postfix)

If I got to [C], and my assumptions are right - next I’m wondering what part of the mailcow setup can I skip?
Is there a components I don’t need to setup?