Should I have multiple GraphQL instances or just a single one?
In case you came across this question, as I noticed it's on the top of results on Google, I also posted this as a Github issue on the graphql-spec repository and got some good responses from core maintainers of the spec. You can want to check it out: https://github.com/graphql/graphql-spec/issues/569
I'll mark this as the accepted answer for now.