In that case, Pulumi permissions are too broad IMHO for what it has to do, an enterprise should adhere to least privilege. Likewise, as I wrote in another comment, the egress security groups are unclear to me (why any traffic at all is needed?) and the image consumed should be pinned to a digest. Or better yet, should be coming from a private enterprise registry, ideally with an attestation that can be verified at runtime.

I am not sure ECS Fargate makes sense vs an ec2 instance to run the workload. This setup alone will cost about $30/month assuming half a vCPU per replica with Fargate, plus about $12 for the memory (1GB/task). 2xt2.micro could be run for ~$20 without even considering reservation discounts etc. Obviously the gap will become even larger at scale, which I suppose might be very interesting for an enterprise.