After some debugging in chrome debugging tools. I found out that introspection config need to be put in apolloServer.
Something like this:
module.exports = ({ env }) => ({
graphql: {
config: {
playgroundAlways: env.bool("ENABLE_GRAPHQL_PLAYGROUND", false),
apolloServer: {
tracing: false,
introspection: env.bool("ENABLE_GRAPHQL_PLAYGROUND", false),
},
},
},
});