It's a bad title, but I'm trying to figure out how to describe what I want.

First, I got my photoprism working thru cloudflare. Now, on the same domain I would like an email address.

So mysite.com gets routed to 56.654.234.12 let's say by cloudflare such that a global user never sees my ip. But mail.mysite.com that's different, they don't proxy email so if you do a reverse lookup you can find the origin IP.

I heard about tunnels so I stupidly signed up for that, only to learn that a tunnel just lets you into an internal network. So an SMTP server can't get emails from outside that way.

Ideally, somehow I could setup one user at Gmail or proton mail, then somehow setup the same or different user...user1@mysite.com and I could then use mailu, mailcow, mail docker to house my user1@mysite.com which routes mail thru Gmail or protonmail. I know all this makes little sense because I don't know the proper way, so that's my question for you smart people who have done this twice over. Could someone point me to the best way of setting up a local mail server that routes thru cloudflare but is not easily reverse looked up? Is that even a problem at all?