Support recurring scheduled emails without add-ons

The submitted context

Gmail can schedule a message for one future time, but it cannot natively repeat that message on a daily, weekly, monthly, or custom schedule. Routine reminders, status requests, invoices, and check-ins therefore require recreating drafts, writing Apps Script, or granting a third-party extension mailbox access. Please extend Schedule send with recurrence rules, an end date or occurrence limit, timezone selection, and a reviewable list of upcoming sends. Each generated message should remain editable or cancellable before delivery, with guardrails against accidental spam or outdated content. Evidence reviewed 2026-08-09: https://support.google.com/mail/answer/9214606 https://workspace.google.com/marketplace/search/recurring%20email