High performance count with where clause and dynamic data
Create a composite index and use only one SELECT statement. That index would either be on (date, amount) or (amount, date). Which one you choose depends on your query and the selectivity for each column.
Imagine an old-school (physical) phone book. You find something by last name, and keep searching for the first name you want (Doe, John).
Sure, columnstore indexex can be useful, but that might also be overkill.  There are specific performance concerns when you modify data frequently and there are no SEEKs in a columnstore index.