Warning: As an aside, this setup creates mid-price r5.large.search OpenSearch instances by default. Nowhere in the boilerplate code or guide is this mentioned. That will run you $134 per month at minimum.
A good rule when working with any sort of cloud service: Everything that can be charged for, will be.
There are plenty of stories of people getting charged massively, and one may wonder whether this has any negative effects on them getting new customers. Unfortunately it's usually not the ones working with it who are the ones making the decision to use AWS or other cloud services, and the ones who are have their minds fully clouded by the propaganda --- I mean marketing.