I use O365 Business (Or whatever the heck they call it now) for my email, so for SMTP on all my devices at home, I use an O365 account with an app password, sending as a distro-group so it can have a custom name

This works, but I don’t like how every device/server has O365 creds in it. I am thinking I should setup an SMTP Relay at home locally, which sends to O365 (Or Sendgrid, etc etc) and then SMTP on local services can just point to that local address

Is this the right way to go about it? What is the current best software do it? I’ve only ever had experience using IIS to do this, and of course I don’t want to be running windows!