Heads up you should probably never host your own email on the same server as your web/worker servers if you’re worried about IP leakage. Your IP is exposed on outbound mail. Using SMTP services like SendGrid won’t help, either.
One can scan the whole IPv4 address space in probably an hour, so you'll find any service you want to find. You might say, "I have a CDN in front of it", but that is just basic firewalling (or reverse proxying) and not really worth of being called "IP obfuscation".
It may be weak security to keep a bit of cash in my cars glovebox rather than in plain sight, but let me tell you how effective it is at keeping my windows from getting smashed...
That reminds me of the good old days of the Interwebs: Your computer is currently broadcasting an IP address!