> TypeScript's type definitions I found are very, very poor, as a relic of the days where versioning was an issue and many have not been fixed.

I've always found it funny that DefinitelyTyped's tag line is "The repository for high quality TypeScript type definitions", but it's an absolutely disastrous system. If it's not a well-used library, definitions there will be woefully out of date. Versioning is a huge issue with it, so it's hard to figure out what definitions actually match the version library you're using. I can only admit that it's an effort that's better than nothing.

The few projects I added types to, the original project owners gladly accepted them into their main repos, which is great since types will "just work" without fuddling with @types packages.