(mySQL Aggregate function, JOINS, and GROUP BY) sakila database project
The problem is you are joining unrelated tables.  If you don't join them, as in

SELECT NOW() AS 'Dorjan Masrussen',
        s.store_id,
        (select sum(p.amount)
           from payment p
           where p.rental_id in (
             select r.rental_id
               from rental r
               join inventory i
                 on i.inventory_id = r.inventory_id
               where i.store_id = s.store_id)) total_sales,
        (select count(*)
           from customer c
           where c.store_id = s.store_id) num_customers,
        (select count(*)
           from inventory i
           where i.store_id = s.store_id) count_inventory,
        (select count(distinct film_id)
           from inventory i
           where i.store_id = s.store_id) count_titles,
        (select sum(f.replacement_cost)
           from inventory i
           join film f on f.film_id = i.film_id
           where i.store_id = s.store_id) inventory_cost,
        (select count(*)
           from rental r
           join inventory i
             on i.inventory_id = r.inventory_id
           where i.store_id = s.store_id) num_rentals_out
  from store as s


you get:

+---------------------+----------+-------------+---------------+-----------------+--------------+----------------+-----------------+
| Dorjan Masrussen    | store_id | total_sales | num_customers | count_inventory | count_titles | inventory_cost | num_rentals_out |
+---------------------+----------+-------------+---------------+-----------------+--------------+----------------+-----------------+
| 2020-03-31 17:32:18 |        1 |    33679.79 |           326 |            2270 |          759 |       46205.30 |            7923 |
| 2020-03-31 17:32:18 |        2 |    33726.77 |           273 |            2311 |          762 |       46415.89 |            8121 |
+---------------------+----------+-------------+---------------+-----------------+--------------+----------------+-----------------+


Total sales and num_rentals_out differ from your correct output.  I wonder who is right.   The Sakila structure diagram, if I'm not mistaken, has it's crow's feet inverted.

The same result can be obtained, while querying inventory  only once, using a CTE, the Common Table Expression "WITH", as follows:

WITH idata as (
  select i.store_id,
         count(*) num,
         count(distinct i.film_id) num_films,
         sum(f.replacement_cost) repl_cost,
         sum((select count(*)
                from rental r
                where r.inventory_id = i.inventory_id)) num_rentals,
         sum((select sum(p.amount)
                from payment p
                where p.rental_id in (
                  select r.rental_id
                    from rental r
                    where r.inventory_id = i.inventory_id
                ))) sum_rentals
    from inventory i
    join film f on f.film_id = i.film_id
    group by i.store_id
)
SELECT NOW() AS 'Dorjan Masrussen',
        s.store_id,
        idata.sum_rentals total_sales,
        (select count(*)
           from customer c
           where c.store_id = s.store_id) num_customers,
        idata.num count_inventory,
        idata.num_films count_titles, 
        idata.repl_cost inventory_cost,
        idata.num_rentals num_rentals_out
  from store as s
  join idata on idata.store_id = s.store_id


Querying the store table can also be dropped, since all we need is the store_id, which we also find in inventory.