Array.push() not working with Mongoose Populate – Javascript

I read another post about this issue, but I was unable to figure out how to apply it to my situation (node js Array.push() not working using mongoose)

This is my Mongoose async populate function, what I want to do is push a value to a final array which includes each review which I will later do something with. However .push() does not work and I always get an empty array; From what I have read it has to do with the for loop being synchronous and not being able to accept async values but im unsure on what to do to fix it

  //Empty array will be populated with all scores
  const allReviewsRating = []
  this.populate("reviews").then(async function (allReviews) {
    for (const review of allReviews.reviews) {
      allReviewsRating.push(review.rating)

    }
    // async.map(review, allReviews.reviews)

  })

But even when I do something like this

  const allReviewsRating = []
  this.populate("reviews").then(async function (allReviews) {
    allReviewsRating.push(`1`)
    for (const review of allReviews.reviews) {
      allReviewsRating.push(review.rating)

    }
    // async.map(review, allReviews.reviews)

  })

The final array is empty which confuses me even more

I was wondering what I need to do in order to get my array to not be empty, and actually have the values I want it to have