One thing to note is the pricing. Clustering is not supported with the micro instance, so if you need it, you must go with at least mq.m5.large [1] and you need three of them, so the total cost is around $620 per month (or closer to $700 for example in eu-central-1).
[1] https://docs.aws.amazon.com/amazon-mq/latest/developer-guide...