Error with asynchronous operation in TypeScript schema validation using Effect library

const UserProfile = Schema.Struct({
    // -- snip --
    Username: Username.Schema.pipe(
        Schema.filterEffect((s) => Effect.orElseSucceed(
            Effect.gen(function* () {
                const db = yield* GetMongoDatabase;
                const coll = db.collection<typeof UserProfile.Type>("user-profile");
               
                // const user = await coll.findOne({ Username: s }); <- This line is the important !

                if (user !== null) {
                    return "there is a user profile with that username";
                }

                return true;
            }),
            () => "unable to check the username for the user profile"
        ))
    ),
    // -- snip --

const user = yield* Effect.promise(() => coll.findOne({ Username: s }));