Exchange 2019 - Custom Internet Receive Connector with Different FQDN and Trusted SSL Certificate

Hello,

I am running Exchange Server 2019 on Windows Server 2022, and I need to create a new "Internet" Receive Connector with an FQDN different from the Default FrontEnd Receive Connector on port 25 (which uses the Exchange server’s FQDN).

However, when I test my SMTP TLS configuration using www.checktls.com, I notice that Exchange presents its self-signed certificate instead of the trusted SSL certificate I have installed.

My Goal:
Create a custom Internet Receive Connector that uses a different FQDN (e.g., mail.mydomain.com).
Ensure that when external senders connect via SMTP, the correct SSL certificate (issued by a trusted CA) is presented instead of the self-signed certificate.

Issues Encountered:
The Default FrontEnd Receive Connector is tied to the Exchange server’s FQDN.
Even after assigning my trusted certificate to the SMTP service, the self-signed certificate is still presented.
I need guidance on how to properly configure the FQDN for SMTP TLS connections and ensure my trusted SSL certificate is used.

In advance thank you.