Here, the more reliable my tech stack is, more predictable (I know when and where it'll likely break), the better.
Instead of focusing on "show I refactor this code like this or that", my day is filled with decisions about product features, how to market them, etc.

We built it with Ruby + Rails, TypeScript and React. None of this is super cutting edge, but it gets the job done.

And that's a big difference compared to other hobby projects.
You work on a hobby project to try out new things, to learn that new language or framework. Here, we want to make money.