You don’t achieve exactly once at the protocol/queue level, but at the service/consumer level. This is why SQS guarantees at-least-once.

It’s generally what you described, but the term I’ve seen is “nonce” which is essentially an ID on the message that’s unique, and you can check against an in-memory data store or similar to see if you’ve already processed the message, and simply return / stop processing the message/job if so.