The article recommends to split up your state files for various advantages, but also expands into how to manage it later in a custom way.

I agree with the splitting, but based on many home-grown automation systems I've seen around this I'd really recommend you to use one of the specialized CI/CD systems that are built around automating these kinds of workflows. Once you reach the "many state files" phase, you'll save a lot of engineering time this way.

They'll take care of, among others, running the right state files, in the right order, with the right parameters. But they'll also take care of many other things you need to run Terraform at scale and with big amounts of engineers (happy to expand but don't want to kitchen-sink this comment).

Disclaimer: Take this with a sensible grain of salt, as I work at Spacelift[0] - one of the TACOS (and of course the one I'll shamelessly link and recommend!).

But really, don't use tools like Jenkins for this as you scale, it'll likely hurt you in the long run.

[0]: https://spacelift.io