Creating an HTML email can feel like stepping back a few years as a web developer. All of our new layout functionality is unavailable to us &mdasj; email clients render the same layout in completely different ways. Just when we think we have it all fixed, another email client shows up with a new set of bugs.
Not too long ago, R'emi Parmentier, an HTML Email developer, ran a session with practical front-end techniques for building modern, cross-client emails.
https://www.smashingmagazine.com/2019/11/html-email-webinar/