Hi there, I'm Riccardo from WRI.
I really like the work you have been doing, those live coding sessions are really nice.
We have been developing a new technology that is allowing you to serve web content from your local machine, we recently published it on GitHub.
https://github.com/WolframResearch/WolframWebEngineForPython
The server is based on some very mature technology and is intended for production, I think it's a perfect fit for the type of applications you are doing (JS frontend with WL backend).
This server is also very useful for developing, because you can develop your APIFunction locally, which allows you to do Print / Echo in order to debug your code and see the output directly in the terminal that is running your server.
Once your APIFunction is coded correctly you can decide how to deploy to production: you can deploy on the Wolfram cloud or use a Wolfram Engine to serve content with your own hardware.
Since I'm the main author of this repo, I would really appreciate a feedback on this technology, so if you have time let us know what you think about it.
Cheers!