For pub/sub yes that's correct. For full info though: Redis later added streams (in 5.x) for the don't-wan't-to-miss case: https://redis.io/topics/streams-intro

I'd need to check, but I think so.

Which is probably why if you don't want loss if consumers go down a proper queue system (RabbitMQ, ActiveMQ, Amazon SQS, Kafka if you don't care about ordering between partitions) is the way I'd go.