I'm now curious (but too lazy to setup and test it) how the following query would fare:

  SELECT meal_items.*, employee_markouts.employee_id, customer_orders.customer_id
  FROM meal_items
  LEFT JOIN employee_markouts ON employee_markouts.meal_item_id = meal_items.id
  LEFT JOIN employees ON employees.id = employee_markouts.employee_id
  LEFT JOIN customer_order_items ON customer_order_items.meal_item_id = meal_items.id
  LEFT JOIN customer_orders ON customer_orders.id = customer_order_items.customer_order_id
  LEFT JOIN customers ON customers.id = customer_orders.customer_id
  WHERE (employees.store_id = 250 AND 
         employee_markouts.created >= '2021-02-03' AND
         employee_markouts.created < '2021-02-04') OR
        (customers.store_id = 250 AND
         customer_orders.created >= '2021-02-03' AND
         customer_orders.created < '2021-02-04')