SendGrid + Microsoft 365

I’m trying to send an email campaign from SendGrid (to avoid potential spam flags set by Microsoft, using a mail subdomain) which has a reply-to address set to an employee’s email (which has an email account setup in ERPNext connected to Exchange via an oauth token).

I have an email account working with sendgrid and an email account working with Microsoft 365. How can I setup an email account that sends through sendgrid with a different reply-to address?