I ought to say some things about json-ld, because I think a lot of people aren't familiar with the details of it.
- You can play with json-ld live here: https://json-ld.org/playground/
- JSON-LD lets you have extensions but map them to local "compacted" shorthands, while still allowing to expand out into unambiguous form.
- JSON-LD does allow converting to a RDF graph, but it's not required. (It is interesting, though.)