I just used the stack I was used to, didn't really turn out to be the best stack for the job...

Kubernetes is completely unnecessary, although I do enjoy using it.

Having a separate API is kinda nice. I could easily spin up a different front-end like an iOS app and share the same API. And I can write all the server code in Ruby instead of JS, which I prefer to do.

But yeah overall, way over-engineered.