Sure, deploying a single app config is much more awkward than it should be. (Build config: Helm, Jsonnet, Cue, kustomize,...? How to deploy: Gitops/CI, manually , Octopus, Tekton, Argo, ... ?)
But the real difficulty is in connecting different parts of your architecture.
The Getting Started example is extremely flawed: for local development you want a local Postgres and Redis, but in production those will either be provided by the environment (RDS etc) or self-managed,but as a separate deployment because the authorization/lifetime/scaling/upgrade requirements are very different.
Local, staging and production are so diverse that you will always need extensive customization. And there is no way around that, because the needs are fundamentally different.
There definitely is an opportunity to make this easier. It would have to either be done with tooling that has extensive integrations with cloud providers, or with a distinct end to end platform.
But I don't see how Acorn helps with that all.