Resend + React Email is the cleanest transactional setup I've used
We moved transactional email to Resend last quarter. Coming from SendGrid, the difference in developer experience is night and day. Templates are just React components (React Email), the API is one POST, and domain auth was automatic.
For pure transactional — receipts, password resets, notifications — I can't think of a reason to use anything heavier on a React/Next stack. Curious how people handle the marketing side though, since Resend's broadcast stuff is newer.