OP is using Apollo Server, which is by far the most common server implementation for GraphQL. It may well be there are issues specific to Apollo, but it's definitely worth getting to the bottom of based on how widely used Apollo is.
There is nothing in the posts that identifies NodeJS as the culprit, and based on the info I'd be very surprised if it was. It seems most likely that the type validation is what is taking so much time. But then again, strong types are one of the main benefits of GraphQL. If anything, I've found Node to be one of the easiest and most "natural" server languages for GraphQL, and I have implemented GraphQL servers in Node, Java and Python.