Why does the developer need to care about the certs and ALBs? The devops engineer you need to set up all those controllers could as well deploy those resources from Terraform.
As I showed in the diagrams from the article this application has a single ALB and a single cert per environment and the internal services only talk to each other through the rabbit MQ queue.
DNS, ALB and TLS certs could be easily handled from just a few lines of Terraform, and nobody needs to touch it ever again.
With EKS you would need multiple controllers and multiple annotations controlling them, and then each controller will end up setting up a single resource per environment.
The controllers make sense if you have a ton of distinct applications sharing the same clusters, but this is not the case here, and would be overkill.