ExpressJS: Adding routes dynamically at runtime

I want to be able to add new routes at runtime without restarting the server with NodeJS & ExpressJS. I made a similiar approach like in this article: https://alexanderzeitler.com/articles/expressjs-dynamic-runtime-routing/
Technically I’m able to add new files and logic at runtime likewise in the article, but the problem is that when no api route was matched I’ll send a 404 JSON respond (as it is supposed to be).