How to pass custom config to GraphQL server when using @loopback/graphql

[mrmodise]

With type-graphql, its possible to pass configurations such as enabling or disabling the playground. See https://typegraphql.com/docs/bootstrap.html. However, in LoopBack (https://loopback.io/doc/en/lb4/GraphQL.html) its not clear where these configs could be passed to optimise the out-of-the-box configs. Any help is welcome