With a CTE it would read a bit more like prql:

  with usa_employees as (
    SELECT
            title,
            country,
            salary,
            (salary + payroll_tax)                   AS gross_salary,
            (salary + payroll_tax + healthcare_cost) AS gross_cost
    FROM  employees
    WHERE country = 'USA'
    AND   (salary + payroll_tax + healthcare_cost) > 0
  )
  select  title,
        country,
        AVG(salary)         AS average_salary,
        SUM(salary)         AS sum_salary,
        AVG(gross_salary)   AS average_gross_salary,
        SUM(gross_salary)   AS sum_gross_salary,
        AVG(gross_cost)     AS average_gross_cost,
        SUM(gross_cost)     AS sum_gross_cost,
        COUNT(*) as emp_count
  from      usa_employees
  group by  title, country
  having    count(*) > 200
  order by  sum_gross_cost
  limit 3

Readability is pretty similar to prql. It would really help in SQL if you could refer to column aliases so you don't have to repeat the expression.