Find all users that have the same reference objects -- mongoose

Question

I have a users with an array of references to another model (sport). Now I want to create a GET route to find users who have common references with one specific user. I just cant figure out, how to do it...... would be great if someone can help :) I tried something like...

router.get("/matches", (req, res) => {
  const { _id } = req.payload;

  User.findById(_id)
  .then((currentUser) => {
     currentUser.sports.map((sportDetails) => {
       sportDetails.map((sportId) => {
         const {_id} = sportId
       })
       return User.find({ sports: { sportId } });
     });
  })
  .then((matches) => {
    res.json(matches)
  })
  .catch((err) => {
    console.log("no matches...", err)
  })
});

user.model

const userSchema = new Schema(
  {
    username: String,
    sports: [{ type: Schema.Types.ObjectId, ref: "Sport" }]
   }
);

sport.model

const sportSchema = new Schema(
  {
    title: String,
    level: String
   }
);