ORDER BY is not working when I try to use this psql query

Question

I have a psql database storing reviews for a certain product.
When the client requests data from the api, it sends in a request with a product_id, count, and a sort as query parameters.

I have this snippit of code below that should query the database and bring back the correct data.

async (query) => {
const sort = {
  relevance: 'helpfulness DESC, date DESC',
  helpfulness: 'helpfulness DESC',
  newest: 'date DESC'
};

const sql = 'SELECT id, product_id, rating, to_timestamp(date / 1000) AS date, summary, body, recommend, reviewer_name, reviewer_email, response, helpfulness, photos FROM reviews WHERE product_id=$1 AND reported=false ORDER BY $2 LIMIT $3'

try {
  const result = await pool.query(sql ,[query.product_id, sort[query.sort] || sort.relevance, query.count || 5]);
  return result;
} catch (error) {
  throw new Error(error);
}}

My issue is that the sort does not apply at all during the query. It will grab the right product_id and also limit the rows that are returned properly but the sort just won't apply.