I've been researching a way to modernize & speed-up a production setup making heavy use of TypeScript Decorators & Metadata.

Sorry for your vibes. Have you read the article?

I don't intend to blame developers who use these APIs incorrectly, none of this is easy. On the contrary I'm trying to explain & review common misconceptions that make developers go to extreme lengths in avoiding these APIs altogether, whereas in my experience mis-uses of these APIs are mostly inconsequential *edit: in comparison to their highly beneficial potential impact*.