Want to set my KumoMTA server in Salesforce as a relay

Hi, how can I configure my kumoMTA server in a Salesforce Starter Edition account as a relay or external email server to achieve high deliverability? By the way, is this a good idea to use my server in Salesforce as an external relay? I am using a Salesforce Starter Edition account that costs $25, and I want to use my server in my Salesforce account as a relay. But Salesforce doesn’t allow to use of Relay in a starter edition account, but I have a friend that doing this in a starter edition account. I don’t know how, but he’s doing well, and he doesn’t tell me that’s why I posted here. If anyone knows, then please let me know. Thanks.

SFDC should accept smtp_auth injections but it really depends on what SF services you are using to route with.

I am using salesforce starter edition account, that’s their basic account

You should investigate if you can inject with SMTP_Auth to that account. I have no idea about current SF product features.