one duplicate row made my consumer send the same receipt 10 times Idempotency

Let the database decide, and put the side effect after the write wins.

const [row] = await db
  .insert(invoices)
  .values({ providerEventId: event.id, ... })
  .onConflictDoNothing({ target: invoices.providerEventId })
  .returning({ id: invoices.id })

if (!row) return   // someone already handled this event, ack and go home

await sendReceipt(row.id)

If no row comes back, this delivery is a duplicate and there is nothing to do. No exception, no retry, no second email.

The broader point: your retries are not the bug. At-least-once is the guarantee you bought when you picked a queue, and anything you put on it will run twice eventually - on redelivery, on a stalled worker, on a deploy. The handler has to be safe under that, always.

Separate "record that it happened" from "do the thing".

Handler one writes the fact in a transaction and nothing else. A second step - an outbox row picked up by another job - sends the email. Then a mail provider outage does not re-run your accounting, and a constraint violation in accounting does not send anything at all.

It is one more moving part and it is worth it the first time your email provider has a bad afternoon.

Generalise it so you stop thinking about it per-handler: every job carries an idempotency key from the producer, and you have a processed_jobs(key primary key, completed_at) table. First statement in the handler inserts the key, in the same transaction as the work. Conflict means you are a duplicate, return.

Boring, portable across every queue you will ever use, and about fifteen lines of shared code.

Set max_retries to 1. Worst case a duplicate sends twice instead of ten times and you have capped the blast radius.

Log the event id and the attempt number on every single run, structured. Next time this happens - and it will, in a different handler - you can answer "was that ten events or one event ten times" in twenty seconds instead of an afternoon of reading mail provider logs.